Composition and method for recycling semiconductor wafers having low-k dielectric materials thereon

ABSTRACT

A removal composition and process for removing low-k dielectric material, etch stop material, and/or metal stack material from a rejected microelectronic device structure having same thereon. The removal composition includes hydrofluoric acid. The composition achieves at least partial removal of the material(s) from the surface of the microelectronic device structure having same thereon, for recycling and/or reuse of said structure, without damage to the underlying polysilicon or bare silicon layer employed in the semiconductor architecture.

This application is filed under the provisions of 35 U.S.C. §111(a) andis a continuation of U.S. patent application Ser. No. 12/093,290 filedon May 9, 2008, which claims priority to International PatentApplication No. PCT/US2006/060696 filed on 9 Nov. 2006, which claimspriority to U.S. Provisional Patent Application No. 60/735,225 filed on9 Nov. 2005, U.S. Provisional Patent Application No. 60/760,969 filed on20 Jan. 2006, U.S. Provisional Patent Application No. 60/805,826 filedon 26 Jun. 2006, and U.S. Provisional Patent Application No. 60/821,631filed on 7 Aug. 2006, which are all hereby incorporated herein in theirentireties.

FIELD OF THE INVENTION

The present invention relates to compositions and processes useful forthe removal of low-k dielectric and other material layers from arejected substrate or article having said material deposited thereon,for recycling/reworking and/or reuse of said substrate or article, andto products manufactured using same.

DESCRIPTION OF THE RELATED ART

The escalating requirements for performance associated with highdensity, ultra large scale integration (ULSI) semiconductor wiring haveincreasingly required the use of low dielectric constant (low-k)insulating layers to increase signal transport speeds as device sizeshave decreased.

Typical low-k materials include carbon doped oxides (CDO) depositedusing commercially available precursors such as SiLK™, AURORA™, CORAL™,or BLACK DIAMOND™, for example using the proprietary BLACK DIAMOND™process. Such CDO's are typically formed using chemical vapor deposition(CVD) processes from organosilane and organosiloxane precursors. CVDcarbon doped oxide low-k dielectrics typically consist of a porous, lowdensity material having an overall dielectric constant less than about3.2 and are used in a variety of semiconductor structures, typically byforming multiple layers of the CDO's within which other semiconductorstructures, such as metal interconnect lines and vias, are formed. Forexample, CDO's may be used as dielectric insulating layers (inter-metaldielectric (IMD) layers), capping layers and/or as gap filling materialfor certain structures.

Frequently, a microelectronic device wafer, for example a siliconsemiconductor wafer, must be scrapped and hopefully recycled followingthe unacceptable processing of layers during the multi-layer devicemanufacturing process or qualification processes. Any number ofprocessing problems may occur, for example, the non-uniform depositionof the CDO layer or a subsequent etching error. A number of qualitycontrol testing methods are performed following selected processingsteps whereby the acceptability of the semiconductor wafer may berejected and “scrapped” for various reasons resulting in a significantnon-productive cost.

The prior art practice has been to send the rejected or scrapped processwafers to wafer suppliers for processing, whereby the dielectric layers,such as CDO layers, are removed from the semiconductor wafer usingchemical and mechanical methods for reuse of said wafer. Following thesuccessful removal of dielectric layers and other features overlying thewafer, the wafer is recycled or reused in a new multi-layersemiconductor device manufacturing process. As semiconductor wafermanufacturing moves to larger diameter wafers, for example 12 inchwafers, scrapping and recycling a process wafer off-site becomesincreasingly more unattractive because of the high non-productive cost.

There is a need in the art to develop a process whereby low-k dielectriclayers, including CDO layers, may be removed from rejectedmicroelectronic devices, e.g., semiconductor wafers, in-house usingimproved compositions, said compositions being compatible with existingmanufacturing processes. Preferably, the process of using saidcompositions to remove low-k dielectric layers from the rejectedmicroelectronic devices does not require a high energy-consumingoxidizing step.

Towards that end, it is an object of the present invention to provide animproved composition and process whereby metal stack materials, etchstop layers, and/or low-k dielectric layers, including CDO layers, maybe removed from rejected microelectronic device structures for in-houserecycling of said structures, whereby the compositions and processes arecompatible with existing manufacturing processes and components.Importantly, the underlying device surface, e.g., silicon, is preferablyundamaged by said removal composition.

In addition to the removal of the metal stack materials, etch stoplayers, and/or low-k dielectric layers while concurrently minimizing thedamage to the underlying substrate material, the composition of theinvention may be formulated to comply with local environmentalrequirements. For example, high fluoride concentrations and high organicsolvent concentrations may make a composition difficult to use in highvolume manufacturing due to wastewater disposal issues. Depending on thelevel of chemical oxygen demand (COD) of the formulation, whereby theCOD of a solution is a measure of the amount of organic compounds thatcan be fully oxidized to carbon dioxide in the presence of a strongoxidant under acidic conditions, the formulation may not be allowed inthe facility wastewater for direct return to the environment. Forexample, in Switzerland, the COD of a wastewater sample must be reducedto between 200 and 1000 mg/L before wastewater or industrial water canbe returned to the environment (Pupunat, L., Sollberger, F., Rychen, P.,“Efficient Reduction of Chemical Oxygen Demand in IndustrialWastewaters,” http://www.csem.ch/corporate/Report2002/pdf/p56.pdf).

If the wastewater contains only fluoride sources (without organicsolvent), a fluoride treatment system may be employed to remove thefluoride from wastewater first, and then the water may be discharged tothe environment. If the wastewater contains only organic solvent(s)(without fluoride source), an organic disposal system, such as anincinerator, may be employed. Disadvantageously, incineration systemsmay not accept wastewater samples containing high fluorideconcentrations because the fluoride source may damage the incineratormaterials of construction.

Accordingly, in addition to providing an improved composition andprocess for the removal of low-k dielectric and other material layersfrom rejected microelectronic device structures for in-house recyclingof said structures, the composition and/or process of using saidcomposition preferably complies with local regulatory standardsassociated with the disposal of said composition.

SUMMARY OF THE INVENTION

The present invention relates to compositions and processes useful forthe removal of low-k dielectric and other material layers, includingcarbon doped oxide material layers, from a rejected microelectronicdevice structure having said material deposited thereon, for recyclingand/or reuse of said microelectronic device structure, and methods ofusing such compositions and products or intermediate productsmanufactured using the same.

In one aspect, the present invention relates to removal compositionsuseful in removing material selected from the group consisting of low-kdielectric material, etch stop material, metal stack material, andcombinations thereof from the surface of a rejected microelectronicdevice structure for recycling of said microelectronic device structure,and methods of making and using the same. The compositions of thepresent invention include hydrofluoric acid.

In another aspect, the present invention relates to a removalcomposition, comprising hydrofluoric acid and water, wherein saidcomposition is further characterized by comprising at least one of thefollowing components (I) and (II):

-   -   (I) at least one amine; or    -   (II) at least one organic solvent, wherein the composition is        substantially devoid of amine species, and        wherein said removal composition is suitable for removing        material selected from the group consisting of low-k dielectric        material, etch stop material, metal stack material, and        combinations thereof from a microelectronic device having said        material thereon.

In still another aspect, the present invention relates to a removalcomposition comprising hydrofluoric acid, amine-N-oxide, and water,wherein said removal composition is suitable for removing materialselected from the group consisting of low-k dielectric material, metalstack material, and combinations thereof from a microelectronic devicehaving said material thereon.

In still another aspect, the present invention relates to a removalcomposition comprising hydrofluoric acid, N-methylmorpholine-N-oxide,and water, wherein said removal composition is suitable for removingmaterial selected from the group consisting of low-k dielectricmaterial, metal stack material, and combinations thereof from amicroelectronic device having said material thereon.

In a further aspect, the present invention relates to a removalcomposition comprising hydrofluoric acid, water, at least onesulfur-containing solvent, and at least one glycol ether, wherein saidcomposition is substantially devoid of amine, and wherein said removalcomposition is suitable for removing material selected from the groupconsisting of low-k dielectric material, etch stop material, metal stackmaterial, and combinations thereof from a microelectronic device havingsaid material thereon.

In a further aspect, the present invention relates to a removalcomposition comprising hydrofluoric acid, water, tetramethylene sulfone,and at least one glycol ether, wherein said composition is substantiallydevoid of amine, and wherein said removal composition is suitable forremoving material selected from the group consisting of low-k dielectricmaterial, etch stop material, metal stack material, and combinationsthereof from a microelectronic device having said material thereon.Preferably, the at least one glycol ether comprises diethylene glycolbutyl ether and the amount of water is in a range from about 10 wt % to80 wt %, based on the total weight of the composition.

Still another aspect relates to a stable removal composition, comprisinghydrofluoric acid, at least one organic solvent, at least one oxidizingagent, at least one chelating agent, and water, wherein the compositionis devoid of amines, and wherein said removal composition is temporallystable and suitable for removing material selected from the groupconsisting of low-k dielectric material, etch stop material, metal stackmaterial, and combinations thereof from a microelectronic device havingsaid material thereon. Preferably, the chelating agent comprises CDTA.

Another aspect of the invention relates to a kit comprising, in one ormore containers, one or more of the following reagents for forming aremoval composition, wherein said removal composition compriseshydrofluoric acid and water, wherein said composition is furthercharacterized by comprising at least one of the following components(I)-(II):

-   -   (I) at least one amine; or    -   (II) at least one organic solvent, wherein the composition is        substantially devoid of amine species,        and wherein the kit is adapted to form a removal composition        suitable for removing material selected from the group        consisting of low-k dielectric material, etch stop material,        metal stack material, and combinations thereof from a        microelectronic device having said material thereon.

In another aspect, the invention relates to a method of removingmaterial from a microelectronic device having said material thereon,said method comprising contacting a microelectronic device structurewith a removal composition for sufficient time to at least partiallyremove material selected from the group consisting of low-k dielectricmaterial, etch stop material, metal stack material, and combinationsthereof, from the microelectronic device structure, wherein the removalcomposition includes hydrofluoric acid and water, and wherein saidcomposition is further characterized by comprising at least one of thefollowing components (I)-(II):

-   -   (I) at least one amine; or    -   (II) at least one organic solvent, wherein the composition is        substantially devoid of amine species.

In a further aspect, the present invention relates to a method ofmanufacturing a microelectronic device, said method comprisingcontacting a microelectronic device structure with a removal compositionfor sufficient time to at least partially remove material selected fromthe group consisting of low-k dielectric material, etch stop material,metal stack material, and combinations thereof from the microelectronicdevice structure having said material thereon, wherein the removalcomposition includes hydrofluoric acid and water, and wherein saidcomposition is further characterized by comprising at least one of thefollowing components (I)-(II):

-   -   (I) at least one amine; or    -   (II) at least one organic solvent, wherein the composition is        substantially devoid of amine species.        Preferably, the contacted microelectronic device structure is        subsequently processed to manufacture a multi-layer device        structure and said device structure is incorporated into the        microelectronic device.

A further aspect of the invention relates to microelectronic devicewafers reclaimed using the methods of the invention comprisingcontacting the rejected microelectronic device wafer with a removalcomposition for sufficient time to at least partially remove materialselected from the group consisting of low-k dielectric material, etchstop material, metal stack material, and combinations thereof from themicroelectronic device, using the methods and/or compositions describedherein, and optionally, incorporating the microelectronic devicestructure into a product (e.g., microelectronic device).

Yet another aspect of the invention relates to improved microelectronicdevices and microelectronic device structures, and productsincorporating same, made using the methods of the invention comprisingcontacting the microelectronic device structure with a removalcomposition for sufficient time to at least partially remove materialselected from the group consisting of low-k dielectric material, etchstop material, metal stack material, and combinations thereof from themicroelectronic device, using the methods and/or compositions describedherein, and optionally, incorporating the microelectronic devicestructure into a product (e.g., microelectronic device).

Another aspect of the invention relates to a method of removing low-kdielectric material from a microelectronic device having said low-kdielectric material thereon, said method comprising:

-   -   contacting the microelectronic device with a removal composition        for sufficient time to at least partially remove said low-k        dielectric material from the microelectronic device, wherein the        removal composition includes hydrofluoric acid and water, and        wherein the pH of a 20:1 dilution of the removal composition in        water is in a range from about 2.5 to about 4.5;    -   contacting the microelectronic device having removal composition        thereon with a neutralizing composition to neutralize the        removal composition on the microelectronic device; and    -   rinsing the microelectronic device having neutralized removal        composition thereon with water to remove the neutralized removal        composition therefrom.

Still another aspect of the invention relates to a method of recycling amicroelectronic device substrate, said method comprising:

-   -   contacting a microelectronic device structure comprising        material selected from the group consisting of low-k dielectric        material, etch stop material, metal stack material, and        combinations thereof with a removal composition for sufficient        time to at least partially remove said material from the        microelectronic device structure to produce a recycled        microelectronic device structure; and    -   applying at least one layer of low-k dielectric material on the        recycled microelectronic device structure,    -   wherein the removal composition includes hydrofluoric acid and        water, and wherein said composition is further characterized by        comprising at least one of the following components (I)-(II):    -   (I) at least one amine; or    -   (II) at least one organic solvent, wherein the composition is        substantially devoid of amine species.

Yet another aspect of the invention relates to a microelectronic devicecomprising a microelectronic device wafer and at least one layerthereon, wherein said at least one layer is selected from the groupconsisting of low-k dielectric material, barrier layer material, metals,metal alloys, and etch stop layers, and wherein the microelectronicdevice wafer is reclaimed. Preferably, the microelectronic device wafercomprises silicon and the reclaimed wafer has a thickness that isgreater than 95% of the thickness of a new wafer, more preferablygreater than 98%, and most preferably greater than 99% of the thicknessof a new wafer.

Another aspect of the invention relates to an article of manufacturecomprising a removal composition of the invention, a microelectronicdevice, and material selected from the group consisting of low-kdielectric material, etch stop material, metal stack material, andcombinations thereof, wherein the removal composition includeshydrofluoric acid and water, and wherein said composition is furthercharacterized by comprising at least one of the following components(I)-(II):

-   -   (I) at least one amine; or    -   (II) at least one organic solvent, wherein the composition is        substantially devoid of amine species.

Other aspects, features and embodiments of the invention will be morefully apparent from the ensuing disclosure and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plot of the etch rate, in Å min⁻¹, of various low-kdielectric materials as a function of temperature.

FIG. 2 is a plot of the etch rate, in Å min⁻¹, of various metal stackmaterials as a function of temperature.

FIG. 3 is a plot of the etch rate, in Å min⁻¹, of various underlyingsilicon-containing materials as a function of temperature.

DETAILED DESCRIPTION OF THE INVENTION, AND PREFERRED EMBODIMENTS THEREOF

The present invention relates to removal compositions and processesuseful for the removal of low-k dielectric and other material layers,including carbon doped oxide material, from a rejected microelectronicdevice structure having said material thereon, for in-house recycling ofsaid microelectronic device structure.

“Microelectronic device” corresponds to semiconductor substrates, flatpanel displays, and microelectromechanical systems (MEMS), manufacturedfor use in microelectronic, integrated circuit, or computer chipapplications. It is to be understood that the term “microelectronicdevice” and “microelectronic device structure” is not meant to belimiting in any way and includes any substrate or structure that willeventually become a microelectronic device or microelectronic assembly.

As used herein, “about” is intended to correspond to ±5% of the statedvalue.

As defined herein, “low-k dielectric material” corresponds to anymaterial used as a dielectric material in a layered microelectronicdevice, wherein the material has a dielectric constant less than about3.5. Preferably, the low-k dielectric materials include low-polaritymaterials such as silicon-containing organic polymers,silicon-containing hybrid organic/inorganic materials, organosilicateglass (OSG), TEOS, fluorinated silicate glass (FSG), and carbon-dopedoxide (CDO) glass. For purposes of this invention, low-k dielectricmaterial further includes silicon nitride materials. It is to beappreciated that the low-k dielectric materials may have varyingdensities and varying porosities.

As used herein, the term “semi-aqueous” refers to a mixture of water andorganic components. Semi-aqueous removal compositions must not damagethe material located adjacent to the low-k dielectric material removedusing said composition. Adjacent materials include bare silicon,polysilicon, and combinations thereof. Depending on the desired results,adjacent materials may also include etch stop-layers and metal stackmaterials. Preferably, less than 100 Å of adjacent materials areremoved, more preferably less than 50 Å, even more preferably less than20 Å, even more preferably less than 10 Å and most preferred less than 1Å of the adjacent materials are removed using the compositions of theinvention.). Preferably, at least 95% of the low-k dielectric isremoved, more preferably at least 99%, even more preferably at least99.9%, and most preferably 100%. It should be appreciated that therewill be occasions when it is desired to remove metal stack materialsand/or etch stop layers, in addition to low-k dielectric materials, inthe process of regenerating the rejected microelectronic devicestructure.

As defined herein, “metal stack materials” correspond to: tantalum,tantalum nitride, titanium nitride, titanium, nickel, cobalt, tungsten,and silicides thereof; copper layers; aluminum layers; Al/Cu layers;alloys of Al; alloys of Cu; hafnium oxides; hafnium oxysilicates;zirconium oxides; lanthanide oxides; titanates; and combinations thereofon the microelectronic device. It is to be appreciated by one skilled inthe art that although the compositions of the invention are described asremoving low-k dielectric materials, the recitation that thecompositions are useful for removing low-k dielectric materials isintended to include the removal of metal stack materials as well, whendesired.

As defined herein, “etch stop layers” include silicon carbide (SiC),silicon carbon nitride (SiCN), silicon carbon oxide (SiCO), siliconoxynitride (SiON), copper, silicon germanium (SiGe), SiGeB, SiGeC, AlAs,InGaP, InP, InGaAs, and combinations thereof. It is to be appreciated byone skilled in the art that although the compositions of the inventionare described as removing low-k dielectric materials, the recitationthat the compositions are useful for removing etch stop layers isintended to include the removal of metal stack materials as well, whendesired.

The requirements of a successful wafer reclamation include, but are notlimited to, zero or negligible front-side, bevel edge, and/or backsidesilicon pitting, less than 50 particles at 0.12 μm, a total thicknessvariation (TTV) of less than about 5 μm, and/or a surface metalcontamination of less than 1×10¹⁰ atoms cm⁻². Bevel edge and backsidecleaning is used to remove photoresist and electroplated copper from theoutermost edge and backside of the device wafer, which reduces particleand metal contamination during subsequent processing. As defined herein,“total thickness variation” corresponds to the absolute differencebetween the maximum and the minimum thickness of a microelectronicdevice wafer as determined using a thickness scan or series of pointthickness measurements known in the art.

It is to be understood that the microelectronic device structure to bereclaimed includes a wafer comprising bare silicon, poly-silicon, andcombinations thereof, and can be any diameter or thicknessconventionally used in the art.

Compositions of the invention may be embodied in a wide variety ofspecific formulations, as hereinafter more fully described.

In all such compositions, wherein specific components of the compositionare discussed in reference to weight percentage ranges including a zerolower limit, it will be understood that such components may be presentor absent in various specific embodiments of the composition, and thatin instances where such components are present, they may be present atconcentrations as low as 0.001 weight percent, based on the total weightof the composition in which such components are employed.

In one aspect, the present invention relates to removal compositionsuseful in removing low-k dielectric and metal stack material from thesurface of a rejected microelectronic device structure for recycling ofsaid microelectronic device structure, and methods of making and usingthe same. The compositions of the present invention include hydrofluoricacid.

In one embodiment of this aspect of the invention, the compositionsinclude at least one amine species, hydrofluoric acid, optionally atleast one organic solvent, optionally at least one additional acidspecies, optionally at least one chelating agent, and optionally water,present in the following ranges, based on the total weight of thecomposition:

component % by weight amine(s) about 1% to about 70.0% hydrofluoric acidabout 1% to about 70.0% optional organic solvent(s) 0 to about 80.0%optional additional acid(s) 0 to about 80% optional chelating agent(s) 0to about 10% optional water 0 to about 50%

In the broad practice of the invention, the removal composition maycomprise, consist of, or consist essentially of at least one aminespecies, hydrofluoric acid, optionally at least one organic solvent,optionally at least one additional acid species, optionally at least onechelating agent, and optionally water. In general, the specificproportions and amounts of amine(s), hydrofluoric acid source(s),optional organic solvent(s), optional additional acid(s), optionalchelating agent(s), and water, in relation to each other, may besuitably varied to provide the desired removal action of the compositionfor the low-k dielectric material and/or processing equipment, asreadily determinable within the skill of the art without undue effort.

Compositions of the invention have a pH value in a range from about 1 toabout 7, more preferably about 2.5 to about 4.5, most preferably about 3to about 3.5, when diluted 20:1 with deionized water.

The amine species may include, but are not limited to, straight-chainedor branched C₁-C₂₀ alkylamines, substituted or unsubstituted C₆-C₁₀arylamines, glycolamines, alkanolamines, and amine-N-oxides including,but not limited to, pyridine; 2-ethylpyridine; 2-methoxypyridine andderivatives thereof such as 3-methoxypyridine; 2-picoline; pyridinederivatives; dimethylpyridine; piperidine; piperazine; triethylamine;triethanolamine; ethylamine; methylamine; isobutylamine;tert-butylamine; tributylamine; dipropylamine; dimethylamine; diglycolamine; monoethanolamine; pyrrole; isoxazole; 1,2,4-triazole; bipyridine;pyrimidine; pyrazine; pyridazine; quinoline; isoquinoline; indole;imidazole; N-methylmorpholine-N-oxide (NMMO); trimethylamine-N-oxide;triethylamine-N-oxide; pyridine-N-oxide; N-ethylmorpholine-N-oxide;N-methylpyrrolidine-N-oxide; N-ethylpyrrolidine-N-oxide;1-methylimidazole; diisopropylamine; diisobutylamine; aniline; anilinederivatives; and combinations thereof. Preferably, the amine speciescomprises isoxazole, TAZ, or combinations thereof.

Alternatively, the amine species may comprise a combined amine-hydrogenfluoride salt. Accordingly, the removal compositions of the presentinvention may include at least one amine-hydrogen fluoride salt,optionally at least one organic solvent, optionally at least one organicacid, optionally at least one chelating agent, and optionally water.Amine-hydrogen fluoride salts are non-volatile and as such, changes inthe solution pH due to evaporation of the amine species is avoided.Amine-hydrogen fluoride salts contemplated herein include, but are notlimited to, any of the above-enumerated amines in combination with HF toform an amine-hydrogen fluoride salt. Preferably, the amine-hydrogenfluoride salt species, when used, comprises isoxazole:HF and/or NMMO:HF.It is to be appreciated that the ratio of amine:hydrogen fluoride saltmay vary from about 1:1 to about 20:1 depending on the conditions of thereaction and the nature of the low-k dielectric material to be removed.

Water may be included in the compositions of the invention in partbecause of its ability to solubilize the fluoride species. Preferably,the water is deionized.

The organic solvent(s), when present, serve as a solvent, assist in thepenetration and dissolution of organic residues, wet the surface of themicroelectronic device structure to facilitate low-k dielectric removaland/or passivate the underlying adjacent materials (e.g., bare silicon,polysilicon, silicon carbide, silicon carbon nitride, and silicon carbonoxide). Organic solvents contemplated herein include, but are notlimited to, alcohols, ethers, pyrrolidinones, glycols, carboxylic acids,and glycol ethers such as methanol, ethanol, isopropanol, butanol, andhigher alcohols (including diols, triols, etc.),2,2,3,3,4,4,5,5-octafluoro-1-pentanol, 1H,1H,9H-perfluoro-1-nonanol,perfluoroheptanoic acid, 1H,1H,7H-dodecafluoro-1-heptanol,perfluoropentanoic acid, 1H,1H,8H,8H-dodecafluoro-1,8-octanediol,2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol, 5H-perfluoropentanoic acid,n-butyl heptafluorobutyrate, tetrahydrofuran (THF),N-methylpyrrolidinone (NMP), cyclohexylpyrrolidinone,N-octylpyrrolidinone, N-phenylpyrrolidinone, methyl formate, dimethylformamide (DMF), dimethylsulfoxide (DMSO), tetramethylene sulfone(sulfolane), diethyl ether, phenoxy-2-propanol (PPh), propriopheneone,ethyl lactate, ethyl acetate, ethyl benzoate, acetonitrile, acetone,ethylene glycol, propylene glycol, dioxane, butyryl lactone, butylenecarbonate, ethylene carbonate, propylene carbonate, dipropylene glycol,amphiphilic species (diethylene glycol monomethyl ether, triethyleneglycol monomethyl ether, diethylene glycol monoethyl ether, triethyleneglycol monoethyl ether, ethylene glycol monopropyl ether, ethyleneglycol monobutyl ether, diethylene glycol monobutyl ether (i.e., butylcarbitol), triethylene glycol monobutyl ether, ethylene glycol monohexylether, diethylene glycol monohexyl ether, ethylene glycol phenyl ether,propylene glycol methyl ether, dipropylene glycol methyl ether,tripropylene glycol methyl ether, dipropylene glycol dimethyl ether,dipropylene glycol ethyl ether, propylene glycol n-propyl ether,dipropylene glycol n-propyl ether (DPGPE), tripropylene glycol n-propylether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether,tripropylene glycol n-butyl ether, propylene glycol phenyl ether, andcombinations thereof), branched fluorinated or non-fluorinatedether-linkage carboxylic acids (CH₃CH₂)_(n)O(CH₂)_(m)COOH, where n=1 to10 and m=1 to 10), unbranched fluorinated or non-fluorinatedether-linkage carboxylic acids (CH₃CH₂)_(n)O(CH₂)_(m)COOH, where n=1 to10 and m=1 to 10), branched fluorinated or non-fluorinated non-etherlinkage carboxylic acids (CH₃(CH₂)_(n)COOH, where n=1 to 10), unbranchedfluorinated or non-fluorinated non-ether linkage carboxylic acids(CH₃(CH₂)_(n)COOH, where n=1 to 10), dicarboxylic acids, tricarboxylicacids, and combinations thereof. In addition, the solvent may compriseother amphiphilic species, i.e., species that contain both hydrophilicand hydrophobic moieties similar to surfactants. Hydrophobic propertiesmay generally be imparted by inclusion of a molecular group consistingof hydrocarbon or fluorocarbon groups and the hydrophilic properties maygenerally be imparted by inclusion of either ionic or uncharged polarfunctional groups. Preferably, the organic solvent comprises sulfolane,butyl carbitol, dipropylene glycol propyl ether, or mixtures thereof.

The optional additional acid(s) assist in breaking up and solubilizingthe cross-linked polymer bonds in the low-k dielectric material.Additional acids contemplated herein include, but are not limited to,boric acid, oxalic acid, succinic acid, citric acid, lactic acid, aceticacid, trifluoroacetic acid, tetrafluoroboric acid, hydrofluoric acid,hydrochloric acid, formic acid, fumaric acid, acrylic acid, malonicacid, maleic acid, malic acid, L-tartaric acid, methyl sulfonic acid,trifluoromethanesulfonic acid, iodic acid, mercaptoacetic acid,thioacetic acid, glycolic acid, sulfuric acid, nitric acid, propynoicacid, pyruvic acid, acetoacetic acid, and combinations thereof.

Chelating agent(s) may be added to reduce or eliminate metalcontaminating species on the surface of the device during waferreclamation. Chelating agent(s) contemplated herein include, but are notlimited to: β-diketonate compounds such as acetylacetonate,1,1,1-trifluoro-2,4-pentanedione, and1,1,1,5,5,5-hexafluoro-2,4-pentanedione; carboxylates such as formateand acetate and other long chain carboxylates; and amides (and amines),such as bis(trimethylsilylamide) tetramer. Additional chelating agentsinclude amines and amino acids (i.e. glycine, alanine, citric acid,acetic acid, maleic acid, oxalic acid, malonic acid, succinic acid,nitrilotriacetic acid, iminodiacetic acid, etidronic acid,ethylenediamine, ethylenediaminetetraacetic acid (EDTA), and(1,2-cyclohexylenedinitrilo)tetraacetic acid (CDTA), andmonoethanolamine (MEA)). Unlike non-fluorinated beta-diketones, whichmay need to be combined with a base to form a deprotonated compoundcapable of chelation, fluorinated beta-diketone chelating agents can beused in the absence of a base. The chelating agent may be introduced tothe composition at the manufacturer, prior to introduction of thecomposition to the device wafer, or alternatively at the device wafer,i.e., in situ. It is further contemplated that in addition to chelatingagent(s), other components may be added to the composition to dilute,maintain and/or increase the concentration of other components in thecomposition.

Such compositions may optionally include additional components,including active as well as inactive ingredients, e.g., surfactants,stabilizers, passivators, dispersants, pH stabilizing agents, oxidants,etc.

Specific embodiments of this aspect of the removal composition may be inconcentrated form and include the following, wherein the components maybe present in the following ranges, based on the total weight of thecomposition:

component % by weight preferred/% by weight amine(s) about 1% to about30.0% about 5% to about 15.0% hydrofluoric acid about 5% to about 45.0%about 15% to about 25.0% organic solvent(s) about 10% to about 60% about20% to about 50% additional acid(s) about 5% to about 25% about 10% toabout 25% water about 10% to about 60% about 15% to about 30%or

component % by weight preferred/% by weight amine-hydrogen about 1% toabout 40.0% about 5% to about 30.0% fluoride salt hydrofluoric acidabout 0.01% to about 5.0% about 1% to about 2% organic solvent(s) about40% to about 75% about 50% to about 70% additional acid(s) about 1% toabout 20% about 5% to about 20% water about 0.01% to about 20% about 1%to about 20%or

component % by weight preferred/% by weight amine-hydrogen about 1% toabout 40.0% about 30% to about 35.0% fluoride salt hydrofluoric acidabout 0.01% to about 5.0% about 1% to about 2% organic solvent(s) about45% to about 75% about 55% to about 70% water about 0.01% to about 10%about 1% to about 2%or

component % by weight preferred/% by weight amine about 1% to about 40%about 15% to about 25% hydrofluoric acid about 5% to about 50% about 35%to about 45% water about 20% to about 80% about 35% to about 45%or

component % by weight preferred/% by weight amine about 1% to about30.0% about 5% to about 20% hydrofluoric acid about 5% to about 50%about 10% to about 30% organic solvent(s) about 1% to about 80% about10% to about 65% water about 1% to about 80% about 15% to about 70%and the pH of a 20:1 dilution of the semi-aqueous amine-containingremoval composition in deionized water is in a range from about 2.5 toabout 4.5. Preferably, the semi-aqueous amine-containing removalcomposition contains less than 30 wt. %, preferably less than 10 wt %,more preferably less than 2 wt %, even more preferably less than 1 wt %and most preferred is devoid of tetrahydrofurfuryl alcohol. In the broadpractice of the invention, the removal composition may comprise, consistof, or consist essentially of any of the foregoing embodiments.

The low-k dielectric materials removed using the removal compositions ofthe invention include CORAL™, BLACK DIAMOND™(hereinafter BD),derivatives of CORAL, derivatives of BD, AURORA®, derivatives ofAURORA®, etc. As used herein, “derivatives of CORAL” and “derivatives ofBD” correspond to CORAL and BD materials, respectively, that weredeposited using alternative, often proprietary, deposition processes.The utilization of a different processing technique will result in aCORAL and BD material that differs from CORAL™ and BLACK DIAMOND™,respectively. Another aspect of the invention relates to the removalcompositions as used and further containing such low-k dielectricresidue.

Further, the foregoing embodiments of the removal composition of theinvention may further include low-k dielectric and metal stack materialresidue(s). Preferably, the low-k dielectric material comprisessilicon-containing compounds that dissolve in the removal composition.In a particularly preferred embodiment, the removal composition includesat least one amine species, hydrofluoric acid, water, material residue,optionally at least one organic solvent, optionally at least onechelating agent, and optionally at least one additional acid species,wherein the material residue includes low-k dielectric material residue,metal stack material residue, and combinations thereof In anotherparticularly preferred embodiment, the removal composition includes atleast one amine-hydrogen fluoride salt species, additional hydrofluoricacid, at least one organic solvent, at least one additional acidspecies, material residue and water, wherein the material residueincludes low-k dielectric material residue, metal stack materialresidue, and combinations thereof.

The embodiments of this aspect of the invention may be formulated in thefollowing Formulations A-BB, wherein all percentages are by weight,based on the total weight of the formulation:

-   Formulation A: Tetrafluoroboric acid 4.7 wt %; Triethanolamine:HF    11.7 wt %; HF 1.7 wt %; Ethylene glycol 39.6 wt %; Sulfolane 10.0 wt    %; Butyl carbitol 15.0 wt %; Water 17.3 wt %-   Formulation B: Tetrafluoroboric acid 4.7 wt %; Pyridine:HF 16.0 wt    %; HF 1.7 wt %; Ethylene glycol 39.6 wt %; Sulfolane 10.0 wt %;    Butyl carbitol 15.0 wt %; Water 13.0 wt %-   Formulation C: Tetrafluoroboric acid 5.9 wt %; Pyridine:HF 8.0 wt %;    HF 1.7 wt %; Ethylene glycol 39.6 wt %; Sulfolane 10.0 wt %; Butyl    carbitol 19.0 wt %; Water 15.8 wt %-   Formulation D: Acetic acid 17.0 wt %; Pyridine:HF 27.0 wt %; HF 1.2    wt %; Ethylene glycol 27.6 wt %; Sulfolane 10.0 wt %; DMSO 16.0 wt    %; Water 1.2 wt %-   Formulation E: Pyridine:HF 32.0 wt %; HF 1.3 wt %; Ethylene glycol    32.4 wt %; Sulfolane 13.0 wt %; DMSO 20.0 wt %; Water 1.3 wt %-   Formulation F: Pyridine:HF 32.0 wt %; Propylene glycol 35.0 wt %;    Sulfolane 13.0 wt %; DMSO 20.0 wt %-   Formulation G: Pyridine:HF 31.1 wt %; HF 1.4 wt %; Propylene glycol    34.1 wt %; Sulfolane 12.6 wt %; DMSO 19.4 wt %; Water 1.4 wt %-   Formulation H: Pyridine:HF 32.0 wt %; HF 1.7 wt %; Ethylene glycol    39.6 wt %; Sulfolane 10.0 wt %; DMSO 15.0 wt %; Water 1.7 wt %-   Formulation I: Acetic acid 13.0 wt %; Isoxazole 7.0 wt %; HF 16.2 wt    %; Ethylene glycol 22.1 wt %; Sulfolane 10.0 wt %; DMSO 15.0 wt %;    Water 16.7 wt %-   Formulation J: Acetic acid 13.0 wt %; 1,2,4-Triazole 7.0 wt %; HF    16.2 wt %; Ethylene glycol 22.1 wt %; Sulfolane 10.0 wt %; DMSO 15.0    wt %; Water 16.7 wt %-   Formulation K: Acetic acid 13.0 wt %; Isoxazole 7.0 wt %; HF 16.3 wt    %; Ethylene glycol 24.0 wt %; Sulfolane 15.0 wt %; Water 24.7 wt %-   Formulation L: Acetic acid 13.0 wt %; Isoxazole 7.0 wt %; HF 16.3 wt    %; Ethylene glycol 24.0 wt %; Sulfolane 10.0 wt %; NMP 13.0 wt %;    Water 16.7 wt %-   Formulation M: Acetic acid 13.0 wt %; Isoxazole 7.0 wt %; HF 16.3 wt    %; Ethylene glycol 24.0 wt %; Sulfolane 10.0 wt %; Methyl carbitol    13.0 wt %; Water 16.7 wt %-   Formulation N: Acetic acid 13.0 wt %; Isoxazole 7.0 wt %; HF 16.3 wt    %; Ethylene glycol 24.0 wt %; Sulfolane 10.0 wt %; Dipropylene    glycol methyl ether 13.0 wt %; Water 16.7 wt %-   Formulation O: Acetic acid 15.0 wt %; Isoxazole 9.0 wt %; HF 17.2 wt    %; Ethylene glycol 25.9 wt %; Sulfolane 15.0 wt %; Water 17.9 wt %-   Formulation P: Isoxazole 10.3 wt %; HF 20.4 wt %; Ethylene glycol    30.7 wt %; Sulfolane 17.2 wt %; Water 21.4 wt %-   Formulation Q: acetic acid 21.1 wt %; Isoxazole 12.0 wt %; HF 23.0    wt %; Sulfolane 20.0 wt %; Water 23.9 wt %-   Formulation R: acetic acid 18.0 wt %; Isoxazole 10.2 wt %; HF 20.2    wt %; Sulfolane 30.4 wt %; Water 21.2 wt %-   Formulation S: acetic acid 26.4 wt %; Isoxazole 15.0 wt %; HF 28.7    wt %; Water 29.9 wt %-   Formulation T: Isoxazole 15.2 wt %; HF 29.1 wt %; Sulfolane 25.4 wt    %; Water 30.3 wt %-   Formulation U: Isoxazole 20.4 wt %; HF 39.0 wt %; Water 40.6 wt %-   Formulation V: 2-ethylpyridine 20.4 wt %; HF 39.0 wt %; Water 40.6    wt %-   Formulation W: 2-Methoxypyridine 20.4 wt %; HF 39.0 wt %; Water 40.6    wt %-   Formulation X: Piperidine 20.4 wt %; HF 39.0 wt %; Water 40.6 wt %-   Formulation Y: NMMO 8.0 wt %; HF 17.6 wt %; Sulfolane 15.0 wt %;    Butyl carbitol 33.0 wt %; Water 26.4 wt %-   Formulation Z: 2-Methoxypyridine 7.0 wt %; HF 15.7 wt %; Sulfolane    61.0 wt %; Water 16.3 wt %-   Formulation AA: NMMO 7.0 wt %; HF 15.7 wt %; Water 77.3 wt %-   Formulation BB: NMMO 7.0 wt %; HF 15.7 wt %; Sulfolane 10.0 wt %;    Water 67.3 wt %

Preferably, the range of weight percent ratios of the components are:about 0.1:1 to about 10:1 etchant(s) relative to amine(s), preferablyabout 1:1 to about 5:1, and most preferably about 2:1 to about 3:1; andabout 1:1 to about 30:1 water relative to amine(s), preferably about 5:1to about 20:1, and most preferably about 10:1 to about 15:1.

In another aspect, the present invention relates to removal compositionsuseful in removing materials selected from the group consisting of low-kdielectric material, etch stop layers, metal stack materials, andcombinations thereof from the surface of a rejected microelectronicdevice structure, wherein said removal compositions are substantiallydevoid of amine species. By reducing the amount of amine present, theoverall cost of the removal composition decreases and many supply chainproblems are minimized. In addition, amines are known to reactexothermically with HF, which can potentially lead to manufacturingissues such as particle generation. As defined herein, “substantiallydevoid” corresponds to less than about 1 wt. %, more preferably lessthan 0.5 wt. %, and most preferably less than 0.1 wt. % of thecomposition, based on the total weight of said composition.

Accordingly, this aspect of the present invention may includehydrofluoric acid and at least one organic solvent. More specifically,the compositions of the invention may include hydrofluoric acid, atleast one organic solvent, water, optionally at least one organic acid,and optionally at least one chelating agent, present in the followingranges, based on the total weight of the composition:

component % by weight hydrofluoric acid about 0.01% to about 50.0%organic solvent(s) about 20% to about 70.0% optional organic acid(s) 0to about 80.0% optional chelating agent(s) 0 to about 10% water about0.01% to 80%

In the broad practice of this aspect of the invention, the removalcomposition may comprise, consist of, or consist essentially ofhydrofluoric acid, at least one organic solvent, water, optionally atleast one organic acid, and optionally at least one chelating agent. Ingeneral, the specific proportions and amounts of hydrofluoric acidsource(s), organic solvent(s), water, optional organic acid(s), andoptional chelating agent(s), in relation to each other, may be suitablyvaried to provide the desired removal action of the composition for thematerials selected from the group consisting of low-k dielectricmaterial, etch stop layers, metal stack materials, and combinationsthereof, and/or processing equipment, as readily determinable within theskill of the art without undue effort.

Preferably, this aspect of the present invention includes at least 10 wt% HF, based on the total weight of the composition. When copper stackmaterial is not to be removed, the removal composition of this aspect isdevoid of oxidizer and/or carbonate-containing species. Further, theamount of water present in the removal composition of this aspect ispreferably in a range from 10 wt % to 80 wt. %, more preferably 10 wt %to about 75 wt %, based on the total weight of the composition.

Compositions of this aspect have a pH value in a range from about 1 toabout 7, more preferably about 2.5 to about 4.5, most preferably about2.8 to about 3.5, when diluted 20:1 with deionized water.

The preferred organic solvent(s), chelating agent(s), and organicacid(s) species were previously introduced hereinabove. Preferably, thewater is deionized.

Such compositions may optionally include additional components,including active as well as inactive ingredients, e.g., surfactants,stabilizers, passivators, chelating agents, dispersants, pH stabilizingagents, oxidants, etc. For example, about 0.01 wt. % to about 10 wt. %surfactant may be added to the removal composition of the invention.Surfactants contemplated include nonionic, anionic, cationic (based onquaternary ammonium cations) and/or zwitterionic surfactants. Forexample, suitable non-ionic surfactants may include fluoroalkylsurfactants, ethoxylated fluorosurfactants, polyethylene glycols,polypropylene glycols, polyethylene or polypropylene glycol ethers,carboxylic acid salts, dodecylbenzenesulfonic acid or salts thereof,polyacrylate polymers, dinonylphenyl polyoxyethylene, silicone ormodified silicone polymers, acetylenic diols or modified acetylenicdiols, alkylammonium or modified alkylammonium salts, and alkylphenolpolyglycidol ether, as well as combinations comprising at least one ofthe foregoing. In a preferred embodiment, the nonionic surfactant may bean ethoxylated fluorosurfactant such as ZONYL® FSO-100 fluorosurfactant(DuPont Canada Inc., Mississauga, Ontario, Canada). Anionic surfactantscontemplated in the compositions of the present invention include, butare not limited to, fluorosurfactants such as ZONYL® UR and ZONYL® FS-62(DuPont Canada Inc., Mississauga, Ontario, Canada), sodium alkylsulfates, ammonium alkyl sulfates, alkyl (C₁₀-C₁₈) carboxylic acidammonium salts, sodium sulfosuccinates and esters thereof, e.g., dioctylsodium sulfosuccinate, and alkyl (C₁₀-C₁₈) sulfonic acid sodium salts.Cationic surfactants contemplated include alkyltetramethylammonium saltssuch as cetyltrimethylammonium bromide (CTAB) and cetyltrimethylammoniumhydrogen sulfate. Suitable zwitterionic surfactants include ammoniumcarboxylates, ammonium sulfates, amine oxides,N-dodecyl-N,N-dimethylbetaine, betaine, sulfobetaine, alkylammoniopropylsulfate, and the like.

Preferably, an embodiment of this aspect of the invention may be presentin concentrated form and includes the following components present inthe following ranges, based on the total weight of the composition:

component % by weight hydrofluoric acid about 5% to about 40% organicsolvent(s) about 10% to about 70% water about 5% to 80%and the pH of a 20:1 dilution of the removal composition in deionizedwater is in a range from about 2.5 to about 4.5. Optionally, about 0.01wt. % to about 10 wt. % surfactant may be added.

Further, the foregoing embodiment of the removal composition of theinvention may further include materials selected from the groupconsisting of low-k dielectric material, etch stop layers, metal stackmaterials, and combinations thereof. Preferably, the materials dissolvein the removal composition.

This embodiment may be formulated in the following Formulations CC-HH,wherein all percentages are by weight, based on the total weight of theformulation:

-   Formulation CC: HF 20.1 wt %; Butyl carbitol 57.5 wt %; Sulfolane    1.5 wt %; Water 20.9 wt %-   Formulation DD: HF 37.4 wt %; Butyl carbitol 21.7 wt %; Sulfolane    2.2 wt %; Water 38.7 wt %-   Formulation EE: HF 20.1 wt %; Butyl carbitol 21.7 wt %; Sulfolane    2.2 wt %; Water 56.0 wt %-   Formulation FF: 10.04% HF, 10.8% butyl carbitol, 2.2% sulfolane and    76.96% water-   Formulation GG: HF 20.1 wt %; Butyl carbitol 10.8 wt %; Sulfolane    2.2 wt %; Water 66.9 wt %-   Formulation HH: HF 20.1 wt %; Butanol 10.8 wt %; Sulfolane 2.2 wt %;    Water 66.9 wt %

Most preferably, the removal compositions of the invention areformulated in the following embodiments, wherein all percentages are byweight, based on the total weight of the formulation:

component of % by weight preferably (% by weight) most preferably (% byweight) HF about 0.01% to about 50% about 5% to about 40% about 10% toabout 40% organic solvent(s) about 10% to about 70% about 10% to about65% about 12% to about 30% or about 50% to about 60% water about 0.01%to 80% about 10% to 80% about 20% to 80%

Most preferably, this aspect of the invention relates to a removalcomposition including hydrogen fluoride, diethylene glycol butyl ether,sulfolane and water. The range of weight percent ratios of thecomponents are: about 0.1:1 to about 10:1 solvent(s) relative toetchant(s), preferably about 0.5:1 to about 5:1, and most preferablyabout 1:1 to about 3:1; and about 0.1:1 to about 10:1 water relative toetchant(s), preferably about 0.5:1 to about 5:1, and most preferablyabout 1:1 to about 3:1. Further, the removal composition may furtherinclude materials selected from the group consisting of low-k dielectricmaterial, etch stop layers, metal stack materials, and combinationsthereof, wherein the material is dissolved in the removal compositionand the removal composition remains viable for its intended use.

In a particularly preferred embodiment of this aspect of the invention,the removal composition includes water, sulfolane, diethylene glycolbutyl ether, and hydrogen fluoride, wherein the amount of water is in arange from 10 wt. % to about 75 wt. %, based on the total weight of thecomposition, with the provision that the composition is substantiallydevoid of amine.

In still another aspect of the invention, the compositions of theinvention include at hydrofluoric acid, at least one organic solvent, atleast one oxidizing agent, and water, with the provision that thecomposition be substantially devoid of amine. This compositionalembodiment is particularly useful for the removal of low-k dielectricmaterial, etch stop layers and/or the metal film stacks without damagingthe underlying device substrate and without the re-deposition orprecipitation of copper on the surface of said substrate. Oxidizingagents contemplated herein include, but are not limited to, hydrogenperoxide (H₂O₂), oxone, oxone tetrabutylammonium salt, ferric nitrate(Fe(NO₃)₃), potassium iodate (KIO₃), potassium permanganate (KMnO₄),nitric acid (HNO₃), ammonium chlorite (NH₄ClO₂), ammonium chlorate(NH₄ClO₃), ammonium iodate (NH₄IO₃), ammonium perborate (NH₄BO₃),ammonium perchlorate (NH₄ClO₄), ammonium periodate (NH₄IO₃), ammoniumpersulfate ((NH₄)₂S₂O₈), sodium persulfate (Na₂S₂O₈), potassiumpersulfate (K₂S₂O₈), tetramethylammonium chlorite ((N(CH₃)₄)ClO₂),tetramethylammonium chlorate ((N(CH₃)₄)ClO₃), tetramethylammonium iodate((N(CH₃)₄)IO₃), tetramethylammonium perborate ((N(CH₃)₄)BO₃),tetramethylammonium perchlorate ((N(CH₃)₄)ClO₄), tetramethylammoniumperiodate ((N(CH₃)₄)IO₄), tetramethylammonium persulfate((N(CH₃)₄)S₂O₈), urea hydrogen peroxide ((CO(NH₂)₂)H₂O₂), peracetic acid(CH₃(CO)OOH), and combinations thereof. The oxidizing agent may beintroduced to the composition at the manufacturer, prior to introductionof the composition to the device wafer, or alternatively at the devicewafer, i.e., in situ.

Preferably, an embodiment of this aspect of the invention may be presentin concentrated form and includes the following components present inthe following ranges, based on the total weight of the composition:

component % by weight preferred/% by weight hydrofluoric acid about 10%to about 40% about 15% to about 25% organic solvent(s) about 10% toabout 80% about 20% to about 55% water about 10% to about 80% about 15%to about 55% oxidizing agent about 0.1% to about 15% about 1% to about10%and the pH of a 20:1 dilution of the removal composition in deionizedwater is in a range from about 2.5 to about 4.5.

Further, the foregoing embodiment of the removal composition of theinvention may further include materials selected from the groupconsisting of low-k dielectric material, etch stop layers, metal stackmaterials, and combinations thereof. Preferably, the materials dissolvein the removal composition.

This embodiment may be formulated in the following Formulations II-KK,wherein all percentages are by weight, based on the total weight of theformulation:

-   Formulation II: HF 18.3 wt %; Butyl carbitol 52.3 wt %; Sulfolane    1.3 wt %; Water 19 wt %; H₂O₂ 9.1 wt %-   Formulation JJ: HF 20.1 wt %; Butyl carbitol 21.7 wt %; Sulfolane    2.2 wt %; H₂O₂ 1 wt %; Water 55.0 wt %-   Formulation KK: HF 20.1 wt %; Butyl carbitol 21.7 wt %; Sulfolane    2.2 wt %; HNO₃ 0.97 wt %; Water 55.3 wt %

In still another aspect of the invention, the compositions of theinvention include at hydrofluoric acid, at least one organic solvent, atleast one oxidizing agent, water, and at least one copper chelatingagent, with the provision that the composition be substantially devoidof amine. This compositional embodiment is particularly useful for theremoval of low-k dielectric material, etch stop layers and/or the metalfilm stacks without damaging the underlying device substrate and withoutthe re-deposition or precipitation of copper on the surface of saidsubstrate.

Preferably, an embodiment of this aspect of the invention may be presentin concentrated form and includes the following components present inthe following ranges, based on the total weight of the composition:

component % by weight preferred/% by weight hydrofluoric acid about 5%to about 30% about 10% to about 20% organic solvent(s) about 5% to about40% about 10% to about 25% water about 40% to about 90% about 50% to 80%oxidizing agent about 0.1% to about 15% about 1% to about 5% chelatingagent about 0.01% to about 5% about 0.1% to about 2%and the pH of a 20:1 dilution of the removal composition in deionizedwater is in a range from about 2.5 to about 4.5.

Further, the foregoing embodiment of the removal composition of theinvention may further include materials selected from the groupconsisting of low-k dielectric material, etch stop layers, metal stackmaterials, and combinations thereof. Preferably, the materials dissolvein the removal composition.

This embodiment may be formulated in the following Formulations LL-QQ,wherein all percentages are by weight, based on the total weight of theformulation:

-   Formulation LL: HF 20.1 wt %; Butyl carbitol 21.7 wt %; Sulfolane    2.2 wt %; H₂O₂ 1 wt %; CDTA 0.15 wt %; Water 54.85 wt %-   Formulation MM: HF 20.1 wt %; Butyl carbitol 21.7 wt %; Sulfolane    2.2 wt %; H₂O₂ 1 wt %; EDTA 0.15 wt %; Water 54.85 wt %-   Formulation NN: HF 20.1 wt %; Butyl carbitol 21.7 wt %; Sulfolane    2.2 wt % H₂O₂ 1 wt %; MEA 0.15 wt %; Water 54.85 wt %-   Formulation OO: HF 10.04 wt %; Butyl carbitol 10.8 wt %; Sulfolane    2.2 wt %; H₂O₂ 1 wt %; CDTA 0.15 wt %; Water 75.81 wt %-   Formulation PP: HF 10.04 wt %; Butyl carbitol 10.8 wt %; Sulfolane    2.2 wt %; H₂O₂ 1 wt %; acac 2 wt %; Water 73.96 wt %-   Formulation QQ: HF 10.04 wt %; Butyl carbitol 10.8 wt %; Sulfolane    2.2 wt %; H₂O₂ 5 wt %; CDTA 0.15 wt %; Water 71.81 wt %

Preferably, the range of weight percent ratios of the components are:about 0.1:1 to about 10:1 etchant(s) relative to oxidant(s), preferablyabout 0.5:1 to about 5:1, and most preferably about 1:1 to about 3:1;about 0.1:1 to about 10:1 solvent(s) relative to oxidant(s), preferablyabout 1:1 to about 5:1, and most preferably about 2:1 to about 3.5:1;about 0.001:1 to about 0.1 chelating agent(s) relative to oxidant(s),preferably about 0.01:1 to about 0.05:1; and about 1:1 to about 30:1water relative to oxidant(s), preferably about 5:1 to about 25:1, andmost preferably about 10:1 to about 20:1.

Importantly, the chelating agent may be introduced to the composition ofthis aspect at the manufacturer, prior to introduction of thecomposition to the device wafer, or alternatively at the device wafer,i.e., in situ. It is further contemplated that in addition to chelatingagent(s), other components may be added to the composition to dilute,maintain and/or increase the concentration of other components in thecomposition.

The low-k dielectric materials removed using the removal compositions ofthe invention include CORAL™, BLACK DIAMOND™ (hereinafter BD),derivatives of CORAL, derivatives of BD, AURORA®, derivatives ofAURORA®, etc. As used herein, “derivatives of CORAL” and “derivatives ofBD” correspond to CORAL and BD materials, respectively, that weredeposited using alternative, often proprietary, deposition processes.The utilization of a different processing technique will result in aCORAL and BD material that differs from CORAL™ and BLACK DIAMOND™,respectively. Another aspect of the invention relates to the removalcompositions as used and further containing such low-k dielectricresidue.

Importantly, the removal compositions of this aspect are also effectiveat concurrently removing polymers, metal stack materials, etch stoplayers, and/or other residue from a surface of the microelectronicdevice. For example, the removal compositions may effectively removelow-k dielectric material from one side of the microelectronic devicewhile concurrently removing polymer and other residue from the otherside of the microelectronic device. As such, as applied tomicroelectronic device manufacturing operations, the removalcompositions of the present aspect of the invention are usefullyemployed to remove material selected from the group consisting of low-kdielectric material, etch stop layers, metal stack materials, andcombinations thereof from rejected microelectronic device structures,including wafers comprising silicon, for recycling and/or reuse of saidstructures. Importantly, the removal compositions of the inventionsatisfy the wafer reclamation requirements, including less than 50particles at 0.12 μm, a total thickness variation less than the industrystandard of 5 μm, and/or a metal surface contamination of less than1×10¹⁰ atoms cm⁻². Furthermore, because of the low TTV, an additionalchemical mechanical polishing (CMP) step, i.e., to planarize thesubstrate subsequent to the wet removal of the materials, may not beneeded to planarize the front-side and backside of the wafer beforereuse. Alternatively, the parameters of the CMP step may be altered suchthat the energy requirements are substantially reduced, e.g., the lengthof time of the polish is shortened, etc. Most preferably, the TTV isless than 3%, more preferably less than 1% and most preferably less than0.5%, subsequent to the removal of the materials from themicroelectronic device substrate.

In addition, it should be appreciated that any of the removalcompositions disclosed herein may be used during (CMP) processes, i.e.,to planarize copper and remove barrier layer materials, to acceleratethe removal of CDO and other low-k dielectric materials, as readilydeterminable by one skilled in the art. Importantly, when theapplication requires stopping on a copper layer, for example during CMPprocessing, and the removal composition includes at least one chelatingagent, the removal composition preferably further includes at least onecopper passivator species. Contemplated copper passivator speciesinclude, but are not limited to, 1,2,4-triazole, benzotriazole (BTA),tolyltriazole, 5-phenyl-benzotriazole, 5-nitro-benzotriazole,3-amino-5-mercapto-1,2,4-triazole, 1-amino-1,2,4-triazole,hydroxybenzotriazole, 2-(5-amino-pentyl)-benzotriazole,1-amino-1,2,3-triazole, 1-amino-5-methyl-1,2,3-triazole,3-amino-1,2,4-triazole, 3-mercapto-1,2,4-triazole,3-isopropyl-1,2,4-triazole, 5-phenylthiol-benzotriazole,halo-benzotriazoles (halo=F, Cl, Br or I), naphthotriazole,2-mercaptobenzoimidizole (MBI), 2-mercaptobenzothiazole,4-methyl-2-phenylimidazole, 2-mercaptothiazoline, 5-aminotetrazole(ATA), 5-amino-1,3,4-thiadiazole-2-thiol,2,4-diamino-6-methyl-1,3,5-triazine, thiazole, triazine,methyltetrazole, 1,3-dimethyl-2-imidazolidinone,1,5-pentamethylenetetrazole, 1-phenyl-5-mercaptotetrazole,diaminomethyltriazine, mercaptobenzothiazole, imidazoline thione,mercaptobenzimidazole, 4-methyl-4H-1,2,4-triazole-3-thiol,5-amino-1,3,4-thiadiazole-2-thiol, benzothiazole, tritolyl phosphate,indiazole, and combinations thereof. Dicarboxylic acids such as oxalicacid, malonic acid, succinic acid, nitrilotriacetic acid, iminodiaceticacid, and combinations thereof are also useful copper passivatorspecies. It is also contemplated herein that the removal compositions ofthe invention may be diluted with a solvent such as water and used as apost-chemical mechanical polishing (CMP) composition to remove post-CMPresidue including, but not limited to, particles from the polishingslurry, carbon-rich particles, polishing pad particles, brush deloadingparticles, equipment materials of construction particles, copper, copperoxides, and any other materials that are the by-products of the CMPprocess. When used in post-CMP applications, the concentrated removalcompositions may be diluted in a range from about 1:1 to about 1000:1solvent to concentrate, wherein the solvent can be water and/or organicsolvent.

In yet another aspect, any of the removal compositions disclosed hereinmay be buffered to a pH in a range from about 5 to about 8, preferablyabout 5.5 to about 7, to minimize corrosion of the materials ofconstruction in the fab, e.g., steel drainage systems and other tools,as readily determinable by one skilled in the art. Contemplatedbuffering species include, but are not limited to organic quaternarybases, alkali bases, alkaline earth metal bases, organic amines,alkoxides, amides, and combinations thereof More specifically, thebuffering species may include benzyltrimethylammonium hydroxide,benzyltriethylammonium hydroxide, benzyltributylammonium hydroxide,dimethyldiethylammonium hydroxide, tetramethyl ammonium hydroxide,tetraethyl ammonium hydroxide, tetrapropyl ammonium hydroxide,tetrabutyl ammonium hydroxide, ammonium hydroxide, potassium hydroxide,cesium hydroxide, rubidium hydroxide, alkyl phosphonium hydroxides, andderivatives thereof, Aniline, Benzimidazole, Benzylamine, 1-Butanamine,n-Butylamine, Cyclohexanamine, Diisobutylamine, Diisopropylamine,Dimethylamine, Ethanamide, Ethanamine, Ethylamine, Ethylenediamine,1-Hexanamine, 1,6-Hexanediamine, Pyrazine, Pyridazine, Urea,N-methylpyrrolidone, diglycolamine, pyridine, triethylamine,monoethanolamine, triethanolamine, aminoethylethanolamine,N-methylaminoethanol, aminoethoxyethanol, dimethylaminoethoxyethanol,diethanolamine, N-methyldiethanolamine, 2 methoxy pyridine, isoxazole,1,2,4 triazole and derivatives thereof.

Most preferably, the removal compositions of the invention areformulated in the following embodiments, wherein all percentages are byweight, based on the total weight of the formulation:

component of % by weight preferably (% by weight) most preferably (% byweight) HF about 0.01% to about 50% about 5% to about 35% about 10% toabout 25% organic solvent(s) about 20% to about 70% about 10% to about65% about 15% to about 30% or about 50% to about 60% water about 0.01%to about 80% about 10% to about 80% about 20% to about 80% oxidizingagent(s) 0 to about 10% about 0.01 to about 7% about 0.1 to about 5%chelating agent(s) 0 to about 5% about 0.01% to about 1% about 0.01% toabout 0.5%

The removal compositions of the invention are easily formulated bysimple addition of the respective ingredients and mixing to homogeneouscondition. Furthermore, the removal compositions may be readilyformulated as single-package formulations or multi-part formulationsthat are mixed at the point of use. The individual parts of themulti-part formulation may be mixed at the tool or in a storage tankupstream of the tool. The concentrations of the respective ingredientsmay be widely varied in specific multiples of the removal composition,i.e., more dilute or more concentrated, in the broad practice of theinvention, and it will be appreciated that the removal compositions ofthe invention can variously and alternatively comprise, consist orconsist essentially of any combination of ingredients consistent withthe disclosure herein.

Accordingly, one aspect of the invention relates to concentratedformulations of the compositions described herein with low amounts ofwater and/or solvent, or alternatively without water and/or solvent,wherein water and/or solvent may be added prior to use to form theremoval compositions of the invention. The concentrated formulations maybe diluted in a range from about 1:10 to 10:1 solvent to concentrate,wherein the solvent can be water and/or organic solvent.

Accordingly, another aspect of the invention relates to a kit including,in one or more containers, one or more components adapted to form theremoval compositions of the invention. The kit may include, in one ormore containers, at least one amine, hydrofluoric acid, optionally atleast one organic solvent, optionally at least one chelating agent,optionally at least one additional acid, and optionally water forcombining at the fab. Alternatively, the kit may include at least oneamine, hydrofluoric acid, at least one organic solvent, and at least oneadditional acid, for combining with the water and/or organic solvent atthe fab. In still another embodiment, the kit may include at least oneamine, hydrofluoric acid, water, and at least one additional acid, forcombining with the water and/or organic solvent at the fab. In yetanother alternative, the kit may include, in one or more containers, atleast one amine-hydrogen fluoride salt, additional hydrofluoric acid, atleast one organic solvent, and optionally at least one additional acid,for combining with water and/or organic solvent at the fab.

Alternatively, the kit may include, in one or more containers,hydrofluoric acid, at least one organic solvent, optionally at least onechelating agent, and optionally at least one organic acid, for combiningwith the water and/or organic solvent at the fab. It should beappreciated that the kit may include any of the components of theforegoing embodiments, in any combination, as readily determined by oneskilled in the art. The containers of the kit should be chemically ratedto store and dispense the component(s) contained therein. For example,the containers of the kit may be NOWPak® containers (Advanced TechnologyMaterials, Inc., Danbury, Conn., USA).

In addition to a liquid solution, it is also contemplated herein thatthe removal compositions may be formulated as foams, fogs, subcriticalor supercritical fluids (i.e., wherein the solvent is CO₂, etc., insteadof water and/or organic solvent(s)).

Importantly and advantageously, the removal compositions dissolvematerials selected from the group consisting of low-k dielectricmaterial, etch stop layers, metal stack materials, and combinationsthereof from the microelectronic device substrate (i.e., bare silicon,polysilicon) rather than delaminate said material therefrom. Dissolutionhas the advantage of minimizing the generation of particulate matterthat may subsequently settle on said substrate as well as substantiallyeliminating clogging of the removal equipment. In addition, theunderlying wafer device remaining following the removal process usingthe compositions of the invention is substantially smooth and undamaged.

In yet another aspect, the invention relates to methods of removal ofmaterials selected from the group consisting of low-k dielectric layers,etch stop layers, metal stack materials, and combinations thereof from amicroelectronic device having said layers thereon using the removalcompositions described herein. For example, low-k dielectric materialsmay be removed while maintaining the integrity of the underlyingpolysilicon, bare Si, etch stop layers (e.g., SiCN, SiCO, SiC, SiON,SiGe, SiGeB, SiGeC, AlAs, InGaP, InP, InGaAs,), and metal stackmaterials. Alternatively, low-k dielectric layers and metal stackmaterials may be removed while maintaining the integrity of theunderlying polysilicon, bare Si layers, and/or etch stop layers (e.g.,SiCN, SiCO, SiC, SiON, SiGe, SiGeB, SiGeC, AlAs, InGaP, InP, InGaAs,).In another alternative, low-k dielectric layers, etch stop layers andmetal stack materials may be removed while maintaining the integrity ofthe underlying polysilicon and bare Si layers.

In a further aspect, the invention relates to methods of removal oflow-k dielectric layers from one side of the microelectronic device andpolymer or other residues from the other side of the microelectronicdevice.

In removal application, the removal composition is applied in anysuitable manner to the rejected microelectronic device having materialto be removed thereon, e.g., by spraying the removal composition on thesurface of the device, by dipping (in a volume of the removalcomposition) of the device including the low-k dielectric material, bycontacting the device with another material, e.g., a pad, or fibroussorbent applicator element, that has said removal composition absorbedthereon, by contacting the device including the material to be removedwith a circulating removal composition, or by any other suitable means,manner or technique, by which the removal composition is brought intoremoval contact with the material to be removed. Further, batch orsingle wafer processing is contemplated herein. The removal processusing the removal compositions may include a static clean, a dynamicclean, or sequential processing steps including dynamic cleaning,followed by static cleaning of the device in the removal composition,with the respective dynamic and static steps being carried outalternatingly and repetitively, in a cycle of such alternating steps.

The removal compositions may be used with a large variety ofconventional cleaning tools, including Verteq single wafer megasonicGoldfinger, OnTrak systems DDS (double-sided scrubbers), Laurellspin-spray tools, SEZ single wafer spray rinse, Applied MaterialsMirra-Mesa™/Reflexion™/Reflexion LK™, and Megasonic batch wet benchsystems.

As applied to microelectronic device manufacturing operations, theremoval compositions of the present invention are usefully employed toremove material selected from the group consisting of low-k dielectricmaterial, etch stop layers, metal stack materials, and combinationsthereof from rejected microelectronic device structures for recyclingand/or reuse of said structures. In addition, it should be appreciatedthat the removal compositions may be used during chemical mechanicalpolishing processes to accelerate the removal of CDO and other low-kdielectric materials or post-CMP processes to remove post-CMP residuematerial.

The compositions of the present invention, by virtue of theirselectivity for such material(s), relative to other materials that maybe present on the microelectronic device structure and exposed to theremoval composition, such as polysilicon, bare Si, etc., to achieve atleast partial removal of the material(s) in a highly efficient manner.

In use of the compositions of the invention for removing materialselected from the group consisting of low-k dielectric material, etchstop layers, metal stack materials, and combinations thereof frommicroelectronic device structures having same thereon, the removalcomposition typically is contacted with the device structure for a timeof from about 30 seconds to about 60 minutes, more preferably about 75sec to about 5 min, the preferred time being dependent on the thicknessof the layer(s) to be removed, at temperature in a range of from about20° C. to about 90° C., preferably about 25° C. to about 60° C., mostpreferably about 25° C. to about 50° C. When etch stop layers are to beremoved, the contacting time may be in a range of from about 5 minutesto about 3 hours at temperature in a range of from about 25° C. to about80°, depending on the thickness of the etch stop layer. Such contactingtimes and temperatures are illustrative, and any other suitable time andtemperature conditions may be employed that are efficacious to at leastpartially remove the material(s) from the device structure, within thebroad practice of the invention. As defined herein, “at least partialdissolution” corresponds to at least 90% dissolution removal ofmaterial, preferably at least 95% dissolution removal of material. Mostpreferably, at least 99% of the material is dissolvably removed usingthe compositions of the present invention.

Following the achievement of the desired removal action, the removalcomposition is readily removed from the microelectronic device to whichit has previously been applied, e.g., by rinse, wash, or other removalstep(s), as may be desired and efficacious in a given end useapplication of the compositions of the present invention. For example,the microelectronic device may be rinsed with deionized water. Inaddition, the microelectronic device may be dried with nitrogen gas orSEZ (spin process technology).

In a further aspect, the present invention relates to methods ofmanufacturing an article comprising a microelectronic device, saidmethod comprising contacting a rejected microelectronic device structurewith the removal compositions of the present invention for sufficienttime to at least partially remove material selected from the groupconsisting of low-k dielectric material, etch stop layers, metal stackmaterials, and combinations thereof from the microelectronic devicestructure to yield a reusable microelectronic device structure, andoptionally further comprising applying one or more layers to thereusable microelectronic device structure, including at least one low-kdielectric material layer, in a subsequent multi-layer microelectronicdevice manufacturing process and incorporating said microelectronicdevice into said article.

Typically, the wet bench tools in the art consist of two baths—one forthe removal composition and one for rinsing the device wafer subsequentto immersion in the removal composition. Disadvantageously, the pH ofthe rinse bath can become very acidic following immersion of the devicewafers having fluoride-containing removal compositions. As previouslydiscussed, a solution having high fluoride concentrations (and highorganic solvent concentrations) may cause significant disposal problems.Accordingly, a process is needed to ensure that the rinse water does notbecome too acidic. Towards that end, the present invention furtherrelates to the incorporation of a third bath in the wet bench tool,specifically a neutralizing bath for use subsequent to the removalcomposition bath but prior to the rinse bath, said bath being useful forneutralizing the high fluoride content of the removal composition thatremains on the device wafer following immersion therein. As such, in yetanother aspect, the present invention broadly relates to a method of atleast partially removing low-k dielectric material from themicroelectronic device structure using the removal compositions of theinvention, neutralizing the wafer surface using a buffer rinse step andrinsing the neutralized wafer with water.

In a preferred embodiment, the present aspect of the invention relatesto a method of removing low-k dielectric material from a microelectronicdevice having said low-k dielectric material thereon, said methodcomprising:

-   -   contacting the microelectronic device with a removal composition        for sufficient time to at least partially remove said low-k        dielectric material from the microelectronic device, wherein the        removal composition includes hydrofluoric acid, and at least one        amine species, and wherein the pH of a 20:1 dilution of the        removal composition in water is in a range from about 2.5 to        about 4.5;    -   contacting the microelectronic device having removal composition        thereon with a neutralizing composition to neutralize the        removal composition on the microelectronic device; and    -   rinsing the microelectronic device having neutralized removal        composition thereon with water to remove the neutralized removal        composition therefrom.

Preferably, the neutralizing compositions include at least one bufferingspecies wherein the pH of the neutralized removal composition is in arange from about 5 to about 9, more preferably in a range from about 6to about 8, and most preferably about 7. Buffering species contemplatedherein include, but are not limited to, commercial color-coded buffersolutions or customized solutions including bases such as hydroxides,carbonates, phosphates, diphosphates, etc., and base/salt mixtures.

The features and advantages of the invention are more fully shown by theillustrative examples discussed below.

EXAMPLE 1

The pH of Formulation A diluted 20:1 with DI water was determined to be3.2.

Bare Si substrates having blanketed BD materials thereon were staticallysoaked in concentrated Formulation A for 2 min to 5 min at 40° C. to 60°C. as indicated in Table 1. The BD material layers were characterized bythe method of depositing the BLACK DIAMOND™ material as well as thethickness of the BD layers. The first bare Si substrate had a blanketedBLACK DIAMOND™ layer deposited using the proprietary BLACK DIAMOND™process and had a thickness of approximately 6,500 Å (hereinafter BDTM).The second bare Si substrate had a blanketed BD derivative materialdeposited using a proprietary deposition process and had a thickness ofapproximately 13,000 Å (hereinafter BDD1). The third bare Si substratehad a blanketed BD derivative material deposited using anotherproprietary deposition process and had a thickness of approximately12,000 Å (hereinafter BDD2).

The results of the static soak are summarized in Table 1 hereinbelow,whereby a “yes” denotes that the specific BD material was substantiallydissolved in the composition at the specified temperature at thespecified time.

TABLE 1 Results of static soak of BD materials in diluted Formulation A.40° C. 50° C. 60° C. time BDTM BDD1 BDD2 BDTM BDD1 BDD2 BDTM BDD1 BDD2 2min no no no yes no yes yes yes yes 3 min yes no yes yes yes yes yes yesyes 4 min yes yes yes yes yes yes yes yes yes 5 min yes yes yes yes yesyes yes yes yes

It can be seen that the dissolution of the BD materials from the surfaceof the substrate was dependent on the time of soaking, the temperatureas well as the thickness of the BD material.

EXAMPLE 2

Blanketed polysilicon was statically soaked in Formulation A for 30minutes at various temperatures and the etch rate of the polysilicondetermined. The results are summarized in Table 2 hereinbelow.

TABLE 2 Results of static soak of polysilicon in Formulation A. PolySietch temperature/° C. rate/Å min⁻¹ 40 1.1 50 1.4 60 1.7

It can be seen that the etch rate of polysilicon in Formulation A wasnegligible in the temperature range studied herein at extreme soakingconditions, e.g., a soak for 30 minutes. This suggests that FormulationA will not damage the underlying polysilicon material.

EXAMPLE 3

Samples of bare silicon, BDTM, BDD1, and BDD2 were statically soaked inFormulation A for 200 minutes at 60° C. to mimic extreme soakingconditions. Following immersion for the specified time, the samples wereremoved from the static soak bath, rinsed, dried and the Atomic ForceMicroscopic (AFM) surface roughness determined. The results are reportedin Table 3 hereinbelow.

TABLE 3 Results of static soak of bare Si and BD materials inFormulation A. control Formulation A bare Si bare Si BDTM BDD1 BDD2 (nm)(nm) (nm) (nm) (nm) 1 m scan 0.174 0.402 0.336 0.405 0.380 5 m scan0.145 0.688 0.296 0.571 0.503

It can be seen that the bare Si substrate was not significantly damagedduring the extreme soak of the respective substrates in Formulation A.For example, the largest numerical change from 0.145 nm to 0.688 nmequates to negligible damage to the surface of the bare Si surface.These results suggest that Formulation A will not damage the underlyingbare Si substrate either.

EXAMPLE 4

The bath life of Formulation A at 60° C. in an open and closedenvironment was evaluated, and the mass of Formulation A was determinedin 24 hr intervals over the course of four days. At t=0, 24, 48, 72 and96 hr, a bare Si substrate having BDTM thereon was immersed in theformulation for 10 minutes and the effectiveness of the formulation forremoving the BDTM from said substrate visually evaluated. The resultsare summarized in Table 4 hereinbelow.

TABLE 4 Results of bath life testing of Formulation A. open bottleclosed bottle time weight loss/g BDTM clean? weight loss/g BDTM clean? 0 hr — yes — yes 24 hr 52.50 yes 0.38 yes 48 hr 11.69 yes 0.09 yes 72hr 4.58 yes 0.06 yes 96 hr 4.33 yes 0.01 yes

The results suggest that Formulation A has a useful bath-life,regardless of whether the formulation became more concentrated over thecourse of four days (i.e., the open bottle wherein water evaporated overtime). In addition, the formulation remained viable over the length ofthe experiment and continued to remove the BDTM from the bare Sisubstrate even after four days. Importantly, no solids were detected inthe bottles after 96 hr at 60° C. or when the bottles were cooled toroom temperature.

EXAMPLE 5

The pH of Formulation B diluted 20:1 with DI water was determined to be3.3.

Bare Si substrates having blanketed BD materials thereon (as describedhereinabove in Example 1) were statically soaked in concentratedFormulation B for 1 min to 2 min at 30° C. to 50° C. as indicated inTable 5. The results of the static soak are summarized in Table 5hereinbelow, whereby a “yes” denotes that the specific BD material wassubstantially dissolved in the composition at the specified temperatureduring the soak for the specified time.

TABLE 5 Results of static soak of BD materials in diluted Formulation B.30° C. 40° C. 50° C. time BDTM BDD1 BDD2 BDTM BDD1 BDD2 BDTM BDD1 BDD2 1min yes no yes yes yes yes yes yes yes 2 min yes yes yes yes yes yes yesyes yes

It can be seen that the dissolution of the BD materials from the surfaceof the substrate was dependent on the time of soaking, the temperatureas well as the thickness of the BD material. In addition, the extent ofdissolution was dependent on the formulation tested. For example,Formulation A at 40° C. and 2 minutes of soaking failed to completelydissolve BDTM however, Formulation B under the same conditions didsubstantially dissolve the BDTM from the bare Si substrate.

EXAMPLE 6

Blanketed polysilicon was statically soaked in Formulation B for 30minutes at various temperatures and the etch rate of the polysilicondetermined. The results are summarized in Table 6 hereinbelow.

TABLE 6 Results of static soak of polysilicon in Formulation B. PolySietch temperature/° C. rate/Å min⁻¹ 30 0.7 40 0.9 50 1.3 60 1.8

It can be seen that the etch rate of polysilicon in Formulation B wasnegligible in the temperature range studied herein at extreme soakingconditions, e.g., a soak for 30 minutes. This suggests that FormulationB will not damage the underlying polysilicon material. In addition,because polysilicon should etch more rapidly that bare Si, it can beassumed that Formulation B will not damage bare Si either.

EXAMPLE 7

Samples of bare silicon, BDTM, BDD1, and BDD2 were statically soaked inFormulation B for 200 minutes at 60° C. to mimic extreme soakingconditions. Following immersion for the specified time, the samples wereremoved from the static soak bath, rinsed, dried and the Atomic ForceMicroscopic (AFM) surface roughness determined. The results are reportedin Table 7 hereinbelow.

TABLE 7 Results of static soak of bare Si and BD materials inFormulation B. control Formulation B bare Si bare Si BDTM BDD1 BDD2 (nm)(nm) (nm) (nm) (nm) 5 m scan 0.145 0.360 0.232 0.280 0.432

It can be seen that the bare Si substrate was not significantly damagedduring the extreme soak of the respective substrates in Formulation B.For example, the largest numerical change from 0.145 nm to 0.432 nmequates to negligible damage to the surface of the bare Si surface.

EXAMPLE 8

The bath life of Formulation B at 50° C. in an open and closedenvironment was evaluated, and the mass of Formulation B was determinedin 24 hr intervals over the course of four days. At t=0, 24, 48, 72 and96 hr, a bare Si substrate having BDTM thereon was immersed in theformulation for 5 minutes and the effectiveness of the formulation forremoving the BDTM from said substrate visually evaluated. The resultsare summarized in Table 8 hereinbelow.

TABLE 8 Results of bath life testing of Formulation B. open bottleclosed bottle time weight loss/g BDTM clean? weight loss/g BDTM clean? 0 hr — yes — yes 24 hr 28.93 yes 0.05 yes 48 hr 20.93 yes 0.21 yes 72hr 13.47 yes 0.16 yes 96 hr 6.25 yes 0.17 yes

The results suggest that Formulation B has a useful bath-life,regardless of whether the formulation became more concentrated over thecourse of four days (i.e., the open bottle wherein water evaporated overtime). In addition, the formulation remained viable over the length ofthe experiment and continued to remove the BDTM from the bare Sisubstrate even after four days. Importantly, no solids were detected inthe bottles after 96 hr at 60° C. or when the bottles were cooled toroom temperature.

EXAMPLE 9

The pH of Formulation C diluted 20:1 with DI water was determined to be3.1.

Bare Si substrates having blanketed BD materials thereon (as describedhereinabove in Example 1) were statically soaked in concentratedFormulation C for 1 min to 2 min at 30° C. to 50° C. as indicated inTable 9. The results of the static soak are summarized in Table 9hereinbelow, whereby a “yes” denotes that the specific BD material wassubstantially dissolved in the composition at the specified temperatureduring the soak for the specified time.

TABLE 9 Results of static soak of BD materials in diluted Formulation C.30° C. 40° C. 50° C. time BDTM BDD1 BDD2 BDTM BDD1 BDD2 BDTM BDD1 BDD2 1min yes no yes yes no yes yes no yes 2 min yes yes yes yes yes yes yesyes yes

It can be seen that the dissolution of the BD materials from the surfaceof the substrate was dependent on the time of soaking, and the thicknessof the BD material. In addition, the dissolution was dependent on theformulation tested. For example, Formulation A at 40° C. and 2 minutesof soaking failed to completely dissolve BDTM, however, Formulation Cunder the same conditions did substantially dissolve the BDTM from thebare Si substrate.

EXAMPLE 10

Blanketed polysilicon was statically soaked in Formulation C for 30minutes at various temperatures and the etch rate of the polysilicondetermined. The results are summarized in Table 10 hereinbelow.

TABLE 10 Results of static soak of polysilicon in Formulation C. PolySietch temperature/° C. rate/Å min⁻¹ 30 0.5 40 0.7 50 0.9 60 1.2

It can be seen that the etch rate of polysilicon in Formulation C wasnegligible in the temperature range studied herein at extreme soakingconditions, e.g., a soak for 30 minutes. This suggests that FormulationC will not damage the underlying polysilicon material. In addition,because polysilicon should etch more rapidly that bare Si, it can beassumed that Formulation C will not damage bare Si either.

EXAMPLE 11

Bare Si substrates having a blanketed CORAL™ layer having a thickness ofapproximately 22,000±1,000 Å thereon were statically soaked inFormulations D-H for 3 min to 5 min at temperatures ranging from 60° C.to 70° C. Following immersion for the specified time, the substrate wasrinsed with DI water, dried, and the amount of CORAL™ removed and theetch rate determined using a Nanospec. The results are summarized inTable 11 hereinbelow.

TABLE 11 Results of static soak of CORAL ™ in Formulations D-H. 60° C.70° C. total etch rate/ total etch rate/ Formulation time loss/Å Å min⁻¹loss/Å Å min⁻¹ D 3 min 6,956 2,319 14,727 4,909 5 min 11,901 2,38022,211 (cleared) >4,442 E 3 min 7,427 2,476 12,025 4,008 5 min 14,0992,820 21,886 (cleared) >4,377 F 3 min 5,349 1,783 — — 5 min 7,422 1,484— — G 3 min 5,612 1,871  8,739 2,913 5 min 8,522 1,704 15,673 3,135 H 3min 7,336 2,445 — — 5 min 13,051 2,610 — —

It can be concluded herein that Formulations D through H providemoderately good CORAL etch rates.

EXAMPLE 12

Bare Si substrates having a blanketed CORAL™ layer having a thickness ofapproximately 22,000±1,000 Å thereon were statically soaked inFormulations I-O for 3 min and/or 5 min at temperatures ranging from 30°C. to 60° C. Following immersion for the specified time, the substratewas rinsed with DI water, dried, and the amount of CORAL™ removed andthe etch rate determined using a Nanospec. The results are summarized inTable 12 hereinbelow.

TABLE 12 Results of static soak of CORAL ™ in Formulations I-O. 30° C.40° C. 50° C. 60° C. total etch rate/ total etch rate/ total etch rate/etch rate/ Form. time loss/Å Å min⁻¹ loss/Å Å min⁻¹ loss/Å Å min⁻¹ totalloss/Å Å min¹ I 3 min 5,764 1,921 16,302 5,434 21,995 >7,33222,895 >7,298 (cleared) (cleared) 5 min 15,263 3,053 21,762 >4,35222,123 >4,425 22,110 >4,422 (cleared) (cleared) (cleared) J 3 min 2,424808  7,479 2,492 10,565 3,521 13,463 4,488 5 min 10,146 2,029 14,8692,974 19,742 3,948 22,283 >4,457 (cleared) K 3 min 10,818 3,606 21,8817,294 21,655 >7,218 22,476 >7,492 (cleared) (cleared) L 3 min 11,6033,868 22,420 >7,473 22,270 >7,423 22,278 >7,426 (cleared) (cleared)(cleared) M 3 min 6,981 2,327 18,537 6,179 21,826 >7,275 22,170 >7,390(cleared) (cleared) N 3 min 9,545 3,182 18,907 6,302 22,260 >7,42022,484 >7,495 (cleared) (cleared) O 3 min 13,554 4,518 21,933 7,31022,066 7,355 22,479 >7,492 (cleared) (cleared)

It can be seen that the use of isoxazole and TAZ in place of pyridine(i.e., formulations D-H) increases CORAL etch rates relative to thosewithout isoxazole and TAZ, and that regardless of the organic solventadded, the etch rates are approximately the same.

EXAMPLE 13

Blanketed polysilicon was statically soaked in Formulations I-O for 30minutes at various temperatures and the etch rate of the polysilicondetermined. The results are summarized in Table 13 hereinbelow.

TABLE 13 Results of static soak of polysilicon in Formulations I-O.PolySi etch PolySi etch PolySi etch PolySi etch rate at rate at rate atrate at 30° C./ 40° C./ 50° C./ 60° C./ Formulation Å min⁻¹ Å min⁻¹ Åmin⁻¹ Å min⁻¹ I 0.3 0.5 0.6 0.9 J 0.9 1.7 2.8 3.9 K — 0.3 — — L — 0.9 —— M — 0.4 — — N — 0.4 — — O — 0.3 — —

It can be seen that the etch rate of polysilicon in Formulations I-O wasnegligible in the temperature range studied herein at extreme soakingconditions, e.g., a soak for 30 minutes. This suggests that FormulationsI-O will not damage the underlying polysilicon material. In addition,because polysilicon should etch more rapidly that bare Si, it can beassumed that Formulations I-O will not damage bare Si either.

EXAMPLE 14

Bare Si substrates having a blanketed CORAL™ layer having a thickness ofapproximately 22,000±1,000 Å thereon were statically soaked inFormulations P-R for 3 min at temperatures ranging from 30° C. to 50° C.Following immersion for the specified time, the substrate was rinsedwith DI water, dried, and the amount of CORAL™ removed and the etch ratedetermined using a Nanospec. The results are summarized in Table 14hereinbelow.

TABLE 14 Results of static soak of CORAL ™ in Formulations P-R. 30° C.50° C. total etch rate/ total etch rate/ Formulation time loss/Å Å min⁻¹loss/Å Å min⁻¹ P 3 min 16,098 5,366 21,907 (cleared) >7,302 Q 3 min21,648 7,216 22,127 (cleared) >7,376 R 3 min 19,546 6,515 22,056(cleared) >7,352

It can be concluded herein that Formulations P-R provide excellent CORALetch rates at relatively low temperatures.

EXAMPLE 15

Blanketed polysilicon was statically soaked in Formulations P-R at 30°C. for 30 minutes and the etch rate of the polysilicon determined. Theresults are summarized in Table 15 hereinbelow.

TABLE 15 Results of static soak of polysilicon in Formulations P-R.PolySi etch Formulation rate/Å min⁻¹ P 0.3 Q 0.2 R 0.3

It can be seen that the etch rate of polysilicon in Formulations P-R wasnegligible at the temperature studied herein at extreme soakingconditions, e.g., a soak for 30 minutes. This suggests that FormulationsP-R will not damage the underlying polysilicon material. In addition,because polysilicon should etch more rapidly that bare Si, it can beassumed that Formulations P-R will not damage bare Si either.

EXAMPLE 16

Bare Si substrates having a blanketed CORAL™ layer having a thickness ofapproximately 22,000±1,000 Å thereon were statically soaked inFormulations S-X for 3 min at 30° C. Following immersion for thespecified time, the substrate was rinsed with DI water, dried, and theamount of CORAL™ removed and the etch rate determined using a Nanospec.The results are summarized in Table 16 hereinbelow.

TABLE 16 Results of static soak of CORAL ™ in Formulations S-X. 30° C.etch rate/ Formulation time total loss/Å Å min⁻¹ S 3 min 22,183 7,394 T3 min 22,339 7,446 U 3 min 22,123 7,374 V 3 min 22,262 7,421 W 3 min22,344 7,448 X 3 min 22,440 7,480

It can be concluded herein that Formulations S-X provide excellent CORALetch rates at very low temperatures.

EXAMPLE 17

Blanketed polysilicon was statically soaked in Formulations S-X at 30°C. for 30 minutes and the etch rate of the polysilicon determined. Theresults are summarized in Table 17 hereinbelow.

TABLE 17 Results of static soak of polysilicon in Formulations S-X.PolySi etch Formulation rate/Å min⁻¹ S 0.1 T 0.2 U 0.2 V 0.3 W 0.3 X 0.3

It can be seen that the etch rate of polysilicon in Formulations S-X wasnegligible at the temperature studied herein at extreme soakingconditions, e.g., a soak for 30 minutes. This suggests that FormulationsS-X will not damage the underlying polysilicon material. In addition,because polysilicon should etch more rapidly that bare Si, it can beassumed that Formulations S-X will not damage bare Si either.

EXAMPLE 18

The pH of Formulation CC diluted 20:1 with DI water was determined to be3.0.

Bare Si substrates having blanketed BD materials thereon (as describedin Example 1) were statically soaked in concentrated Formulation CC for1 min at 30° C. to 50° C. as indicated in Table 18. The results of thestatic soak are summarized in Table 18 hereinbelow, whereby a “yes”denotes that the specific BD material was substantially dissolved in thecomposition at the specified temperature at the specified time.

TABLE 18 Results of static soak of BD materials in diluted FormulationCC. 30° C. 40° C. 50° C. time BDTM BDD1 BDD2 BDTM BDD1 BDD2 BDTM BDD1BDD2 1 min yes yes yes yes yes yes yes yes yes

It can be seen that the BD materials were etched from the surface of thesubstrate and were not dependent on the process conditions evaluated,including time of soaking, the temperature, or the thickness of the BDmaterial.

EXAMPLE 19

Blanketed polysilicon (initial thickness of approximately 970 Å) wasstatically soaked in Formulation CC for 30 minutes at varioustemperatures and the etch rate of the polysilicon determined. Theresults are summarized in Table 19 hereinbelow.

TABLE 19 Results of static soak of polysilicon in Formulation CC. PolySietch temperature/° C. rate/Å min⁻¹ 30 0.96 40 0.99 50 1.83

It can be seen that the etch rate of polysilicon in Formulation CC waslow in the temperature range studied under extreme soaking conditions,e.g., a soak for 30 minutes. This suggests that Formulation CC will notdamage the underlying polysilicon material.

EXAMPLE 20

Samples of bare silicon, BDTM, BDD1, and BDD2 were statically soaked inFormulation CC for 15 minutes at 40° C. and/or 200 minutes at 60° C. tomimic extreme soaking conditions. Following immersion for the specifiedtime, the samples were removed from the static soak bath, rinsed, driedand the Atomic Force Microscopic (AFM) surface roughness determined Theresults are reported in Table 20 hereinbelow.

TABLE 20 Results of static soak of bare Si and BD materials inFormulation CC. control Formulation A bare Si bare Si BDTM BDD1 BDD2Temperature (nm) (nm) (nm) (nm) (nm) 5 m scan 40° C. 0.145 0.144 0.204 —— 5 m scan 60° C. 0.145 1.060 0.606 0.681 0.534

It can be seen that the bare Si substrate was not significantly damagedduring the extreme soak of the respective substrates in Formulation CC.For example, the largest numerical change from 0.145 nm to 1.060 nmequates to negligible damage to the surface of the bare Si surface.These results suggest that Formulation CC will not damage the underlyingbare Si substrate either.

EXAMPLE 21

The bath life of Formulation CC at 40° C. in an open and closedenvironment was evaluated, said bath life being greater than 48 hrs. ASi substrate having BDTM thereon was immersed in the formulation for 5minutes and it was determined that the formulation effectively removedthe BDTM from said substrate within 5 minutes.

Further, the results suggest that Formulation CC has a useful bath-life,regardless of whether the formulation became more concentrated over thecourse of two days (i.e., the open bottle wherein water evaporated overtime). In addition, the formulation remained viable over the length ofthe experiment and continued to remove the BDTM from the Si substrateeven after two days. Importantly, no solids were detected in the bottlesafter 48 hr at 40° C. or when the bottles were cooled to roomtemperature.

EXAMPLE 22

Silicon substrates having a blanketed CORAL™ layer having a thickness ofapproximately 22,000±1,000 Å thereon were statically soaked inFormulation CC for 2 min at 40° C. Following immersion for the specifiedtime, the substrate was rinsed with DI water, dried, and the amount ofCORAL™ removed and the etch rate determined using a Nanospec. It wasdetermined that 22,042 Å of CORAL™ was removed and thus the etch ratewas 11,021 Åmin⁻¹. It can be concluded herein that Formulation CCprovides excellent CORAL etch rates at relatively low temperatures.

EXAMPLE 23

A silicon substrate having a blanketed CORAL™ layer was staticallysoaked in Formulation CC for 200 minutes at 60° C. to mimic extremesoaking conditions. Following immersion, the sample was removed from thestatic soak bath, rinsed, dried and the Atomic Force Microscopic (AFM)surface roughness determined. The RMS roughness (5 μm scan) of the bareSi after processing was determined to be 0.845 nm.

EXAMPLE 24

Separate bare Si substrates having blanketed TEOS, silicon nitride,AURORA™, CORAL™, BLACK DIAMOND™, OSG, FSG, ultra low-k dielectric (ULK)or copper film layers thereon were statically soaked in Formulation CCat various temperatures. Following immersion for the specified time, thesubstrate was rinsed with DI water, dried, and the amount of filmremoved and the etch rate determined using a Nanospec. The results aresummarized in Table 24 hereinbelow and illustrated in FIG. 1.

TABLE 24 Results of static soak of film layers in Formulation CC. EtchRate at Etch Rate at Etch Rate at Etch Rate at Material 30° C./Å min⁻¹40° C./Å min⁻¹ 50° C./Å min⁻¹ 60° C./Å min⁻¹ TEOS 10,751 ± 1269 16,010 ±508 19,394 ± 477 25,193 ± 445 silicon nitride 166 ± 3   319 ± 20  473 ±19  755 ± 43 AURORA ™ 9,422 ± 127 10,612 ± 104 15,836 ± 164 27,797 ± 760CORAL ™ 4,161 ± 214 12,177 ± 360  20,269 ± 1206 25,793 ± 797 BLACK13,038 ± 450  15,656 ± 430 19,497 ± 420 26,031 ± 490 DIAMOND ™ OSG 6,498± 200  8,670 ± 180 12,401 ± 180 17,062 ± 150 FSG 20,928 ± 572   26,244 ±3421 36,601 ± 823  49,596 ± 3400 ULK 41,548 ± 317  — — — copper  1.4 ±0.2   1.0 ± 0.4   0.1 ± 0.1   0.4 ± 0.6

It can be seen that Formulation CC efficiently removes the many low-kdielectric variations, with the overall efficiency dependent on theremoval temperature chosen. Importantly, Formulation CC did notcompromise copper materials that were exposed to said formulation.

EXAMPLE 25

The etch rates of blanketed Ta, TaN, TiN, Cu, poly-Si, SiC, SiCN (A) andSiCN (B) (where SiCN (A) and SiCN (B) represent two differentproprietary silicon carbinitride samples) were determined followingstatic immersion of each sample in Formulation CC at temperaturesranging from 30° C. to 60° C. The etch rates were determined using aNanoSpec. The results are reported in Table 25 and illustratedschematically in FIGS. 2 and 3.

TABLE 25 Results of static soak of film layers in Formulation CC. ER atER at ER at ER at 30° C./ 40° C./ 50° C./ 60° C./ Material Å min⁻¹ Åmin⁻¹ Å min⁻¹ Å min⁻¹ Cu 0 ± 0 0 ± 0 0 ± 0 0 ± 0 Ta 133 ± 27  476 ± 1111839 ± 54  2798 ± 76  TaN 20 ± 13 26 ± 2  49 ± 15 57 ± 3  TiN 85 ± 23130 ± 10  257 ± 28  391 ± 20  poly-Si 0.54 ± 0.08 0.90 ± 0.19 1.11 ±0.14 1.67 ± 0.07 SiC 0.20 ± 0.03 0.20 ± 0.01 0.21 ± 0.02 0.26 ± 0.02SiCN (A) 1.11 ± 0.02 1.19 ± 0.03 1.32 ± 0.05 1.58 ± 0.13 SiCN (B) 3.37 ±0.09 7.64 ± 1.13 12.67 ± 0.67  33.98 ± 3.78 

It can be seen that the Ta, TaN, and TiN metal stack materials can beremoved using the formulation of the present invention, however, coppermaterial was not readily removed at the temperatures investigated. Toassist with the removal of copper layers, 40 g of Formulation CC wasmixed with 4 g of 30% hydrogen peroxide and the low-k and metal stackmaterials immersed therein (see Formulation II herein). The etch rate ofthe low-k dielectric materials was unchanged following the inclusion ofH₂O₂ in Formulation CC, however, the etch rate of the copper wasimmeasurable because the copper layer was etched so rapidly. Inaddition, the etch rate of the TiN was increased when immersed inFormulation II.

Regarding the SiCN etch rates in the presence of Formulation CC, it canbe hypothesized that the oxygen content of the SiCN layers impacted theetch rate of the material. Although not wishing to be bound by theory,it is thought that the higher the oxygen content of the SiCN film, themore robust the film material and thus the lower the etch rate.

Samples of bare Si, SiC and SiCN (A) were further processed inFormulation CC at extreme static conditions (60° C. for 200 minutes),rinsed, dried and analyzed using AFM. It was determined that theprocessed wafers had low rms roughness and as such, bare Si, SiC andSiCN(A) were not significantly damaged in the presence of FormulationCC.

EXAMPLE 26

Three separate experiments were performed to demonstrate the advantagesof neutralizing the removal composition present on the device waferprior to rinsing said wafer in water.

The first experiment included cleaning a device wafer with FormulationCC for 3 minutes at 50° C. followed by rinsing said wafer in a deionized(DI) water bath for 1 min, wherein the volume of Formulation CC was thesame as the volume of DI water in the rinse bath. The pH of the DI waterwas measured before and after the rinsing step. The pH of the DI waterbefore the rinse step was 5.82 and the pH of the DI water subsequent tothe rinse step was 2.98, demonstrating that the residue removalcomposition (i.e., formulation CC) significantly impacts the pH of therinse solution (see also Table 26 hereinbelow).

The second experiment included immersion of the device wafer informulation CC for 3 minutes at 50° C., followed by immersion of thedevice wafer in the neutralizing buffer bath for 1 minute, and lastlyimmersion in the DI water rinse bath for 1 minute. The neutralizingbuffer bath had a pH of approximately 7 prior to immersion therein.Similarly to the first experiment, the volume of removal compositionbath, neutralizing buffer bath and rinse bath is approximately the same.The pH of the DI water bath and the neutralizing buffer bath weremeasured before and after the rinse step. The results are reported inTable 26.

TABLE 26 pH of baths following immersion of device wafers therein.Experiment No. Rinsing Solution pH before rinse pH after rinse 1 DIwater 5.82 2.98 2 pH 7 buffer 7 6.985 DI water 5.9 6.852 3 pH 10 buffer10 9.907 DI water 5.91 8.704

It can be seen that the pH of the DI water bath in the second experimentactually increased following immersion of the device wafer havingneutralized removal composition thereon.

The third experiment included immersion of the device wafer informulation CC for 3 minutes at 50° C., followed by immersion of thedevice wafer in the neutralizing buffer bath for 1 minute, and lastlyimmersion in the DI water rinse bath for 1 minute. The neutralizingbuffer bath had a pH of approximately 10. Similar to the firstexperiment, the volume of removal composition bath, neutralizing bufferbath and rinse bath is approximately the same. The pH of the DI waterbath and the neutralizing buffer bath was measured before and after therinse step and the results reported in Table 26. It can be seen that thepH of the DI water bath in the third experiment actually increasedsubstantially following immersion of the device wafer having neutralizedremoval composition thereon.

Importantly, these experiments demonstrate that the fluoride source isreadily neutralized using buffer baths and as such, the DI wastewatermay be incinerated as discussed in the background of the invention.Advantageously, the buffer baths of the invention did not damage theunderlying silicon-containing layers (e.g., bare Si, SiC, SiCN,polysilicon, etc.).

In order to investigate the effects of loading on the buffer bath, anexperiment was performed whereby six samples were cleaned with removalcomposition, e.g., formulation CC, for 3 minutes at 50° C., followed bythe immersion of the sample having removal composition thereon in thesame pH 7 neutralizing bath, followed by the immersion of the samplehaving neutralized removal composition thereon in the same DI waterrinse bath. The three-step experiment was serially performed six times.The results are reported in Table 27 hereinbelow.

TABLE 27 pH of DI water following serial immersion of six samples.Experiment No. Rinsing Solution pH before rinse pH after rinse buffer7.0 7.003 DI water 5.933 1 pH 7 buffer (step 1) 6.973 DI water (step 2)6.903 2 pH 7 buffer (step 1) 6.895 DI water (step 2) 6.903 3 pH 7 buffer(step 1) 6.882 DI water (step 2) 6.903 4 pH 7 buffer (step 1) 6.813 DIwater (step 2) 6.894 5 pH 7 buffer (step 1) 6.74 DI water (step 2) 6.8836 pH 7 buffer (step 1) 6.698 DI water (step 2) 6.885

It can be seen that the buffer bath aids in maintaining the DI waterbath pH at about pH 7 even after multiple, serial rinsing steps.

EXAMPLE 27

Several different experiments were performed to formulate removalcompositions that varied depending on the disposal requirements butstill effectively removed low-k dielectric material from themicroelectronic device without damaging the underlyingsilicon-containing substrate.

EXAMPLE 27A

Formulation CC was buffered with tetramethylammonium hydroxide (TMAH),or monoethylamine (MEA) and the resulting solutions had measured pHvalues of 6. Unfortunately, the solutions underwent phase separation andwere discarded. Formulation CC was then buffered with triethylamine(TEA) to form a solution having a pH of 7.4 and a solution having a pHof 5.5. In both cases, the solutions including TEA remained in one phaseand blanketed samples of CORAL®, BD and poly-Si were immersed in eachsolution at 50° C. and the etch rates of each determined using aNanoSpec. In each case, buffered formulation CC displayed anunacceptably fast etch rate of the underlying silicon-containing layer(Si damage was observed) and an unacceptably slow etch rate of the low-kdielectric material.

EXAMPLE 27B

The HF in Formulation CC was replaced with approximately 20 wt. %tetrabutylammonium fluoride (TBAH) or approximately 20 wt. % borofluoricacid. Blanketed samples of CORAL®, BD and poly-Si were immersed in eachsolution at 50° C. and the etch rates of each determined using aNanoSpec. It was concluded that in formulation CC, the best fluoridesource remains HF.

EXAMPLE 27C

Hydroxide-based formulations having a pH of about 13.7 were investigatedas an alternative to fluoride-based removal compositions. Blanketedsamples of CORAL®, BD and poly-Si were immersed in each solution at 50°C. and the etch rates of each determined using a NanoSpec. It wasconcluded that acidic, fluoride-based formulations are superior tohydroxide-based formulations at removing low-k dielectric material fromthe surface of the microelectronic device.

EXAMPLE 27D

Formulation CC was diluted with water, diethylene glycol monobutyl ether(BC) or 1-phenoxy-2-propanol (PPh) in order to decrease the overall HFconcentration (1 part formulation CC to x parts diluting solvent). Thesesolutions would have the advantage of having low HF concentrations andas such, could be disposed of by incineration. Blanketed samples ofCORAL®, BD and poly-Si were immersed in each solution at the specifiedtemperature for the specified length of time and the etch rates of eachdetermined using a NanoSpec. The results using the formulation dilutedwith water, BC and PPh are shown in Tables 28, 29 and 30, respectively.

TABLE 28 Etch rates in Å min⁻¹ of samples immersed in formulationdiluted with water at 60° C. sample Time/min dilution ratio ER/Å min⁻¹CORAL 2  1:10 0 2 1:1 2365 BD 2  1:10 residue remains 2 1:1 residueremains poly-Si 30 1:1 2.5

TABLE 29 Etch rates in Å min⁻¹ of samples immersed in formulationdiluted with BC at 60° C. sample Time/min dilution ratio ER/Å min⁻¹CORAL 2  1:10 0 2 1:1 962 BD 2  1:10 0 2 1:1 ~6500 poly-Si 30 1:1 1.6

TABLE 30 Etch rates in Å min⁻¹ of samples immersed in formulationdiluted with PPh at 50° C. sample Time/min dilution ratio ER/Å min⁻¹CORAL 10 1:9 0 5 1:4 2457 3 1:2 >7000 2 1:1 9884 BD 3 1:4 ~6500 3 1:2~6500 3 1:1 ~6500 poly-Si 30 1:9 0.43 1:4 0.33 1:2 0.30 1:1 0.33

It can be seen that the underlying layer etch rate (poly-Si) in theformulation diluted with water is too high for the purposes of thisinvention. In addition, all formulations diluted at a ratio of 1:10 or1:9 did not etch the low-k dielectric materials at an acceptable rate.

Importantly, the 1:1 and 1:2 dilutions with PPh both had an acceptablelow-k dielectric etch rate and a negligible underlyingsilicon-containing layer etch rate. Advantageously, these compositionsdiluted with PPh have a much lower concentration of HF than formulationCC and as such, disposal issues are reduced.

EXAMPLE 27E

A three-step process of removing low-k dielectric material from thesurface of a microelectronic device was investigated. BD wafers wereimmersed in a 20 wt. % HF solution for 1 min or 5 min at 50° C. In bothcases, BD residue was visually observed on the wafer followingimmersion. Thereafter, the wafers were immersed in a 97.5 wt. % BC/2.5wt. % sulfolane composition for 1 min or 5 min at 50° C. Again, BDresidue was visually observed on the wafer. Thereafter the wafer wasimmersed in water, dried and the surface imaged using SEM. Themicrographs clearly illustrated that BD residues remained on the surfaceof the wafer at the conclusion of the three-step process which indicatesthat the three-step process as described herein using the components ofFormulation CC is not a viable option.

EXAMPLE 27F

Formulation DD represents a variation of Formulation CC having a lowerorganic solvent concentration and a higher fluoride concentration, sothat the formulation had a lower COD count while still having a highlow-k dielectric etch rate and a low underlying layer etch rate.

Blanketed samples of CORAL®, BD and poly-Si were immersed in formulationDD at 50° C. for the specified length of time and the etch rates of eachdetermined using a NanoSpec. The results are reported in Table 31hereinbelow.

TABLE 31 Etch rates in Å min⁻¹ of samples immersed in formulation DD at50° C. sample Time/min ER/Å min⁻¹ CORAL 1 21,973 BD 1 >6400 poly-Si 300.47

It can be seen that Formulation DD provided a high low-k dielectricremoval rate and a low poly-Si removal rate, and would be a viableoption when high concentrations of HF are acceptable.

EXAMPLE 27G

Formulation EE represents a variation of Formulation DD having a lowerfluoride concentration and the same organic solvent concentration, asintroduced hereinbelow.

Blanketed samples of CORAL®, BD and poly-Si were immersed in formulationEE at various temperatures and the etch rates of each determined using aNanoSpec. The results are reported in Table 32 hereinbelow.

TABLE 32 Etch rates in Å min⁻¹ of samples immersed in formulation EE atvarious temperatures. sample Temperature/° C. ER/Å min⁻¹ CORAL 50 25,00060 28,633 BD 30 >2184 (cleared in 3 min) 40 >3214 (cleared in 2 min)50 >6500 (cleared in 1 min) 60 >6500 (cleared in 1 min) poly-Si 30 0.64(30 min) 40 0.89 (30 min) 50 0.93 (30 min) 60 1.28 (30 min)

It can be seen that Formulation EE provided a high low-k dielectricremoval rate and a low poly-Si removal rate, and would be a viableformulation for the removal of low-k dielectric materials frommicroelectronic devices for recycling of same. Notably, formulation EEremoves Ta and TiN after immersion for 10 min at 60° C.,disadvantageously with delamination, but cannot dissolve TaN or Cu underthe same conditions.

Samples of bare Si, and BD wafers were further processed in FormulationEE at extreme static conditions (60° C. for 200 minutes), rinsed, driedand analyzed using AFM. It was determined that the bare Si of theprocessed wafers was not significantly damaged by Formulation EE asdemonstrated by the low rms surface roughness.

EXAMPLE 28

As seen in Example 27G, formulation EE can remove BD and CORAL withoutsubstantially damaging the underlying device substrate, e.g., poly-Si.That said, formulation EE does not readily remove metal films. Asintroduced hereinabove, oxidizing agents, such as hydrogen peroxide andnitric acid may be added to the formulations to enhance the concurrentremoval of metal films from the surface of the device substrate withoutdamaging said substrate. Formulations JJ and KK represents variations offormulation CC including oxidizing agents.

Blanketed samples of Cu (˜1166 Å), TaN (˜1600 Å), TiN (˜1200 Å), Ta(˜4200 Å), BD (˜6400 Å) and CORAL® (˜21000 Å) were immersed informulation JJ at various temperatures for various lengths of time andthe etch rates of each determined using a NanoSpec. The results arereported in Table 33 hereinbelow.

TABLE 33 Results of static soak of blanketed sample in Formulation JJ.30° C. 40° C. 50° C. 60° C. etch rate/ etch rate/ etch rate/ etch rate/Sample time removed? Å min⁻¹ removed? Å min⁻¹ removed? Å min⁻¹ removed?Å min¹ Cu 10 min  yes >1,166 yes >1,166 yes >583 yes >389 5 min yes yesyes yes 3 min — — yes yes 1 min yes yes no no TaN 3 min yes >1,600yes >1,600 yes >530 yes >530 1 min yes yes no no TiN 5 min — >1,200— >1,200 — >400 yes >240 3 min — — yes no 1 min yes yes no no Ta 1 minyes >1,200 yes >1,200 yes >400 yes >240 BD 5 min — >6,400 — >6,400— >6,400 yes >6,400 3 min — — yes no 1 min yes yes some res some resCORAL 5 min — >21,000 — >21,000 — >21,000 yes >21,000 3 min — — yes yes1 min yes yes yes some res

It can be seen that formulation JJ readily removed the low-k and metalfilms within 1 minute at 60° C., however, for the Cu sample,re-deposition and/or precipitates were observed.

Importantly, the oxidizing agent may be introduced to the composition atthe manufacturer, prior to introduction of the composition to the devicewafer, or alternatively at the device wafer, i.e., in situ. It isfurther contemplated that in addition to oxidizing agent(s), othercomponents may be added to the composition to dilute, maintain and/orincrease the concentration of other components in the composition.

EXAMPLE 29

Based on the re-deposition results of Example 28, chelating agents wereadded to the formulations including oxidizing agents. Chelating agentscontemplated herein include ethylenediaminetetraacetic acid (EDTA),(1,2-cyclohexylenedinitrilo)tetraacetic acid (CDTA), monoethanolamine(MEA), and acetylacetone (acac). In each case, the recited amount ofeach chelating agent was added to formulation JJ to form formulations LLthrough QQ, as introduced above, and blanketed samples of Cu, TaN, TiN,Ta, BD and CORAL® were immersed therein at various temperatures forvarious lengths of time and the etch rates of each determined using aNanoSpec.

With formulation LL, the CORAL, BD, Cu, TiN, Ta and TaN were all removedfrom the device substrate within 3 minutes at 50° C. Importantly, nometal precipitates were observed at the cross-section or backside of thedevice substrate. The etch rate of poly-Si was unmeasureable because ofPoly-Si film delamination.

With formulations MM and NN, the CORAL, BD, Cu, TiN, Ta and TaN were allremoved from the device substrate within 3 minutes at 50° C., however,metal precipitates were observed at the cross-section of the devicesubstrate. The etch rate of poly-Si was determined to be 2 Å min⁻¹ and2.1 Å min⁻¹ for formulations MM and NN, respectively.

With formulation OO, the CORAL, BD, Cu, TiN, Ta and TaN were all removedfrom the device substrate within 5 minutes at 50° C., and no metalprecipitates were observed at the cross-section or backside of thedevice substrate. The etch rate of poly-Si was determined to be 2.1 Åmin⁻¹.

With formulation PP, the CORAL, BD, Cu, TiN, Ta and TaN were all removedfrom the device substrate within 3 minutes at 50° C., however, metalprecipitates were observed at the cross-section of the device substrate.The etch rate of poly-Si was determined to be about 3.2 Å min⁻¹ and thedevice surface was uneven.

Comparing the results, it can be seen that Formulation OO displayed themost favorable results whereby the low-k and metal materials werereadily removed from the device substrate and no Cu re-deposition orprecipitation was observed on the processed substrate. Importantly,separate tests relating to the addition of chelating agents toformulation EE (i.e., devoid of oxidizing agent) and the staticimmersion of blanketed Cu wafers therein revealed that the Cu would notdissolve in a composition including chelating agents but not oxidizingagents.

The combination of oxidizing agent and chelating agent was furtherinvestigated to confirm the prevention of Cu re-deposition in ahydrofluoric acid-based composition during the etching process of metalfilms and/or low-k dielectric materials. In each case, 0.2 wt. % ofCuCl₂, CuSO₄, Cu(NO₃)₂ or Cu(acac)₂ was added to separate compositionsincluding 10.04% HF, 10.8% butyl carbitol, 2.2% sulfolane and 76.76%water. A bare silicon wafer was statically immersed in each separatecomposition for 5 minutes at room temperature (RT) and 50° C., and 1%H₂O₂ and/or 0.5% CDTA were added, and the extent of copper residuethereon was observed. The results are reported in Table 34 hereinbelow.

TABLE 34 Precipitation of copper at the surface of a bare Si wafer inthe presence of various additives formulation formulation formulationformulation including additive? including CuCl₂ including CuSO₄including Cu(NO₃)₂ Cu(acac)₂ none Cu deposited on Cu deposited on Cudeposited on Cu deposited on wafer at RT and wafer at RT and wafer at50° C. and wafer at 50° C. and 50° C. 50° C. part of the wafer at partof the wafer at RT RT 1% H₂O₂ Cu deposited on Cu deposited on no Cu (butsome no Cu (but some wafer at RT and wafer at 50° C. but no residualmatter) on residual matter) on 50° C. Cu (but some the wafer at RT orthe wafer at RT or residual matter) on 50° C. 50° C. the wafer at RT0.5% CDTA^(‡) Cu deposited on at RT and 50° C., red- at RT and 50° C.,red- at RT and 50° C., red- wafer at RT and brown precipitate brownprecipitate brown precipitate 50° C. observed on wafer; observed onwafer; observed on wafer; precipitate soluble in precipitate soluble inprecipitate soluble in water water water both 1% red-brown no Cu orresidues on at RT and 50° C., no at RT and 50° C., no H₂O₂ andprecipitates on wafer at RT; no Cu Cu or residues on Cu or residues onthe 0.5% CDTA wafer at both RT (but some residue) the wafer wafer and50° C.; on wafer at 50° C. precipitate soluble in water ^(‡)0.6% CuCl₂instead of 0.5% CuCl₂.

It can be seen that when both the oxidizing agent and the chelatingagent were present in the composition, no copper deposition at the bareSi wafer was observed using any of the copper-containing compositions.Importantly, the red-brown precipitates observed are not re-depositedcopper compounds because they were readily soluble in water. In otherwords, redeposition of metals, e.g., copper, onto the device wafer isnegligible using the compositions of the invention.

Furthermore, it was surprisingly discovered that when both the oxidizingagent and the chelating agent were present in the compositions of theinvention, the composition had an extended shelf-life. For example,formulation QQ stored at room temperature for 49 days still removed˜5000 Å copper in 10 sec and a ˜9000 Å three-layer film includingcopper/TaN/low-k in 1 minute. The same formulation stored at 40° C. for35 days removed ˜5000 Å copper in 10 sec and a ˜9000 Å three-layer filmincluding copper/TaN/low-k in 1 minute.

EXAMPLE 30

Blanketed samples of Cu (˜1166 Å), TaN (˜1600 Å), TiN (˜1200 Å), Ta(˜1200 Å), BD (˜6400 Å) and CORAL® (˜21000 Å) were immersed informulations AA, EE or FF at 50° C. for 5 minutes and the etch rates(ER) of each determined using a NanoSpec. The results are reported inTable 35 hereinbelow.

TABLE 35 formulation BD CORAL Cu TaN Ta TiN AA delamination;delamination; ER = 2 Å ER = 27 Å film partially ER = 74 Å residue onresidue on min⁻¹ min⁻¹ dissolved; min⁻¹; film wafer wafer residue ondelaminated wafer unevenly EE removed removed ER = 3 Å ER = 18 Å ER >276 Å ER = 98 Å within 2 min within 2 min min⁻¹ min⁻¹ min⁻¹; min⁻¹; filmremoved in 5 min delaminated unevenly FF removed removed ER = 15 Å ER =15 Å partially ER = 55 Å within 5 min within 5 min min⁻¹ min⁻¹ dissolvedmin⁻¹; film delaminated unevenly

It can be seen that Formulations AA, EE and FF attack the metal filmsand barrier layer materials. Importantly, when the concentration of HFand butyl carbitol is decreased (formulation FF), the etch rate ofcopper increased while the etch rate of TaN, Ta and TiN all decreased.As such, it is predicted that a composition having a low concentrationof HF plus barrier layer inhibiting agents will reduce the etch rate ofthe barrier layer materials, especially Ta and TiN.

In order to further decrease the etch rate of Ta and TiN, theconcentration of HF, butyl carbitol and NMMO was varied and some metalinhibitors added. It was determined that lowering the concentration ofHF and/or adding inhibitors such as polyacrylic acid and 1,2,4-triazoledecreased the etch rate of Ta while the concentration of NMMO was thedetermining factor to lowering the etch rate of TiN. Importantly,however, there is a minimum concentration of HF of about 10 wt. % belowwhich the BD and CORAL may not dissolve completely at process conditionsof 50° C. for 5 minutes.

It is noted that formulation AA is an HAP-free formulation.

EXAMPLE 31

Blanketed samples of BD and poly-Si were immersed in each solution for30 minutes at 60° C. and the etch rates of each determined using aNanoSpec. It was determined that the BD dissolved in both FormulationsGG and HH in less than 1 min at 60° C. and that the poly-Si etch rate inFormulations GG and HH were 1.42 Å min⁻¹ and 0.54 Å min⁻¹, respectively.

***

Accordingly, while the invention has been described herein in referenceto specific aspects, features and illustrative embodiments of theinvention, it will be appreciated that the utility of the invention isnot thus limited, but rather extends to and encompasses numerous otheraspects, features, and embodiments. Accordingly, the claims hereafterset forth are intended to be correspondingly broadly construed, asincluding all such aspects, features, and embodiments, within theirspirit and scope.

What is claimed is:
 1. A method of recycling a microelectronic devicewafer, said method comprising contacting a microelectronic devicestructure comprising the wafer and material selected from the groupconsisting of low-k dielectric material, etch stop material, metal stackmaterial, and combinations thereof with a removal composition forsufficient time to remove said material from the microelectronic devicestructure to produce a recycled wafer, wherein the removal compositioncomprises hydrofluoric acid, at least one organic solvent, and water,wherein the at least one organic solvent comprises a species selectedfrom the group consisting of diethylene glycol butyl ether,tetramethylene sulfone, and combinations thereof.
 2. The method of claim1, wherein at least 90% of said material is removed.
 3. The method ofclaim 1, wherein at least 95% of said material is removed.
 4. The methodof claim 1, wherein at least 99% of said material is removed.
 5. Themethod of claim 1, wherein said contacting is carried out for a time offrom 30 seconds to 60 minutes at temperature in a range of from 20° C.to 90° C.
 6. The method of claim 1, wherein the removal compositionfurther comprises at least one additional species selected from thegroup consisting of at least one organic acid, at least one chelatingagent, and combinations thereof.
 7. The method of claim 1, wherein theremoval composition further comprises material dissolved therein,wherein said material is selected from the group consisting of low-kdielectric material, metal stack material, and combinations thereof. 8.The method of claim 1, wherein the low-k dielectric material comprisesdielectric material selected from the group consisting ofsilicon-containing organic polymers, silicon-containing hybrid organicmaterials, silicon-containing hybrid inorganic materials, organosilicateglass, TEOS, fluorinated silicate glass, silicon nitride, andcarbon-doped oxide glass.
 9. The method of claim 1, wherein the etchstop material comprise a material selected from the group consisting ofsilicon carbon nitride, silicon carbon oxide, silicon oxynitride,silicon germanium, SiGeB, SiGeC, AlAs, InGaP, InP, InGaAs, andcombinations thereof.
 10. The method of claim 1, wherein the metal stackmaterial comprises a material selected from the group consisting oftantalum, tantalum nitride, titanium nitride, titanium, nickel, cobalt,tungsten, and silicides thereof; aluminum; alloys of Al; hafnium oxides;hafnium oxysilicates; zirconium oxides; lanthanide oxides; titanates;and combinations thereof.
 11. The method of claim 1, wherein the removalcomposition comprises HF, water, tetramethylene sulfone, and diethyleneglycol butyl ether.
 12. The method of claim 6, comprising chelatingagent, wherein said chelating agent comprises a species selected fromthe group consisting of acac, hfac, tfac, formate, acetate,bis(trimethylsilylamide) tetramer, amines, glycine, alanine, citricacid, acetic acid, maleic acid, oxalic acid, malonic acid, succinicacid, nitrilotriacetic acid, iminodiacetic acid, etidronic acid,ethylenediamine, EDTA, CDTA, monoethanolamine, and combinations thereof.13. The method of claim 6, comprising chelating agent, wherein saidchelating agent comprises CDTA.
 14. The method of claim 1, furthercomprising using the recycled wafer, subsequent to the removal of saidmaterial therefrom, in a microelectronic device manufacturing process.15. The method of claim 1, further comprising incorporating the recycledwafer into a microelectronic device.
 16. The method of claim 1, whereinthe recycled wafer includes a parameter selected from the groupconsisting of: less than about 3% total thickness variation; less thanabout 1×10¹⁰ metal atoms cm⁻²; less than 50 particles at 0.12 μm; lessthan 5% front-side pitting; less than 5% backside pitting; andcombinations thereof.